bluuebunny/crossref_metadata_2025 huggingface dataset:
Fitness and the level of homozygosity in a social insect
Authors: HAAG‐LIAUTARD C. , VITIKAINEN E. , KELLER L. , SUNDSTRÖM L.
Published: December 2008

To date very few studies have addressed the effects of inbreeding in social Hymenoptera, perhaps because the costs of inbreeding are generally considered marginal owing to male haploidy whereby recessive deleterious alleles are strongly exposed to selection in males. Here, we present one of the first studies on the effects of queen and worker homozygosity on colony performance. In a wild population of the ant Formica exsecta, the relative investment of single‐queen colonies in sexual production decreased with increased worker homozygosity. This may either stem from increased homozygosity decreasing the likelihood of diploid brood to develop into queens or a lower efficiency of more homozygous workers at feeding larvae and thus a lower proportion of the female brood developing into queens. There was also a significant negative association between colony age and the level of queen but not worker homozygosity. This association may stem from inbreeding affecting queen lifespan and/or their fecundity, and thus colony survival. However, there was no association between queen homozygosity and colony size, suggesting that inbreeding affects colony survival as a result of inbred queens having a shorter lifespan rather than a lower fecundity. Finally, there was no significant association between either worker or queen homozygosity and the probability of successful colony founding, colony size and colony productivity, the three other traits studied. Overall, these results indicate that inbreeding depression may have important effects on colony fitness by affecting both the parental (queen) and offspring (worker) generations cohabiting within an ant colony.
Lovesick: immunological costs of mating to male sagebrush crickets
Authors: LEMAN J. C. , WEDDLE C. B. , GERSHMAN S. N. , KERR A. M. , OWER G. D. , ST JOHN J. M. , VOGEL L. A. , SAKALUK S. K.
Published: December 2008

A growing body of evidence suggests that resources invested in reproduction often come at the expense of the ability to mount an immune response. During mating, female sagebrush crickets, Cyphoderris strepitans, consume the ends of the male’s hind wings and ingest his haemolymph. Previous research has shown that this behaviour impairs the ability of males to secure additional matings. One hypothesis to account for this effect is that wing wounding triggers an energetically costly immune response, such that nonvirgin males are unable to sustain the costly acoustical signalling needed to attract additional females. To test this hypothesis, we injected virgin males with lipopolysaccharides (LPS) to provoke an immune response, and monitored their mating success in the field. LPS‐injected virgin males took significantly longer to mate than sham‐injected virgin males, and spent significantly less time calling. We also compared virgin, nonvirgin and experimentally wing‐wounded virgin males with respect to: (1) their ability to encapsulate a foreign invader via the accumulation of haemocytes and deposition of melanin and (2) baseline levels of phenoloxidase (PO), a key enzyme in the biochemical cascade leading to the production of melanin. Although encapsulation ability did not differ with reproductive experience, virgin males had significantly higher levels of PO than either nonvirgin or experimentally wing‐wounded virgin males. These results suggest that wing‐wounding alone is sufficient to impair male immunity, and that males trade‐off investment in reproduction and immunity.
On the mechanism of rejuvenation of ageing detached bean leaves by low‐concentration stressors
Authors: Nyitrai P. , Kovács E. , Király I. , Óvári M. , Keresztes Á.
Published: December 2008

The effect of low concentrations of some stress‐inducing compounds of different toxicity and chemical nature, such as Cd and Pb salts or DCMU, was investigated on the senescence of chloroplasts in detached primary leaves of bean (Phaseolus vulgaris L.). After 1 week of senescence followed by root development from the petiole, these agents stimulated chlorophyll accumulation and photosynthetic activity (14CO2 fixation) as compared to the control, thus inducing rejuvenation. Low‐concentration stressors increased the level of active cytokinins in roots and leaves during the treatment, as monitored by the Amaranthus betacyanin bioassay and high‐pressure liquid chromatography. The lithium ion, an inhibitor of the PIP2‐IP3/DAG signal transduction pathway, abolished the stimulating effect of stressors, both in roots (retarding cytokinin synthesis) and consequently also in leaves (reducing cytokinin‐dependent chlorophyll accumulation). This suggests the involvement of the PIP2‐IP3/DAG signal transduction pathway in generation of these consecutive organ‐specific responses.
Calcyon is necessary for activity‐dependent AMPA receptor internalization and LTD in CA1 neurons of hippocampus
Authors: Davidson Heather Trantham , Xiao Jiping , Dai Rujuan , Bergson Clare
Published: December 2008

Calcyon is a single transmembrane endocytic protein that regulates clathrin assembly and clathrin‐mediated endocytosis in the brain. Ultrastructural studies indicate that calcyon localizes to spines, but whether it regulates glutamate neurotransmission is not known. Here, we show that deletion of the calcyon gene in mice inhibits agonist‐stimulated endocytosis of α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptors (AMPARs), without altering basal surface levels of the GluR1 or GluR2 subunits. Whole‐cell patch‐clamp studies of hippocampal neurons in culture and CA1 synapses in slices revealed that knockout (KO) of calcyon abolishes long‐term synaptic depression (LTD), whereas mini‐analysis in slices indicated basal transmission in the hippocampus is unaffected by the deletion. Further, transfection of green fluorescent protein‐tagged calcyon rescued the ability of KO cultures to undergo LTD. In contrast, intracellular dialysis of a fusion protein containing the clathrin light‐chain‐binding domain of calcyon blocked the induction of LTD in wild‐type hippocampal slices. Taken together, the present studies involving biochemical, immunological and electrophysiological analyses raise the possibility that calcyon plays a specialized role in regulating activity‐dependent removal of synaptic AMPARs.
The Cotton Influence Index: An Examination of U.S. Cotton Subsidies
Authors: Gokcekus Omer , Fishler Richard
Published: December 2008

Given the lack of a bill or amendment specific to cotton, we introduce a Cotton Influence Index to capture legislators’ influence in championing the cause of the cotton growers during the hearings of the Farm Security and Rural Investment Act of 2002. Regression analyses reveal a relationship between Cotton Influence Index and campaign contributions, cotton farmland, party affiliation, and ideology. Tobit analysis indicates a significant relationship between different “actions and participations” by representatives to advance the interest of cotton—that is, components of this index and their future cotton political action committees’ (PACs) contributions to them.
Public Investment and Industry Incentives in Life‐Science Research
Authors: Wang Chenggang , Xia Yin , Buccola Steven
Published: December 2008

Life‐science research has shifted rapidly from the public to the private sector, raising questions about government's remaining role. We shed light on the issue by employing a dynamic investment‐response model to examine the public's impact on industry life‐science research effort and success. We find that government expenditures in both basic biological research and agricultural and medical science create substantial spillovers for private firms. The spillovers are, unfortunately, partly nullified by government competition for scarce research inputs. Yet even after accounting for such competition, public investment has been strongly complementary to private investment. Indeed, opportunities created through public research are the principal source of growth in industry life sciences.
The Role of Spatial Attention in Nonconscious Processing
Authors: Finkbeiner Matthew , Palermo Romina
Published: December 2008

Recent findings from the masked priming paradigm have revealed a surprising influence of higher-level cognitive systems (i.e., attention) on nonconscious cognitive processes. These data have effectively undermined the long-standing assumption in cognitive science that nonconscious processes are carried out independently of attention and have quickly led to the opposite view that attention is a prerequisite for nonconscious processes. Here we present evidence for a middle position by showing that the dependence of nonconscious processes on attention varies with the type of information to be processed. Specifically, we found that nonconsciously perceived faces engaged cognitive processes regardless of attention, whereas nonface stimuli engaged cognitive processes only when attended. These qualitatively different patterns suggest two distinct processing routes: one that is modulated by visual attention and one that is not.
Tonic Activity Level in the Right Prefrontal Cortex Predicts Individuals' Risk Taking
Authors: Gianotti Lorena R.R. , Knoch Daria , Faber Pascal L. , Lehmann Dietrich , Pascual-Marqui Roberto D. , Diezi Christa , Schoch Cornelia , Eisenegger Christoph , Fehr Ernst
Published: December 2008

Human risk taking is characterized by a large amount of individual heterogeneity. In this study, we applied resting-state electroencephalography, which captures stable individual differences in neural activity, before subjects performed a risk-taking task. Using a source-localization technique, we found that the baseline cortical activity in the right prefrontal cortex predicts individual risk-taking behavior. Individuals with higher baseline cortical activity in this brain area display more risk aversion than do other individuals. This finding demonstrates that neural characteristics that are stable over time can predict a highly complex behavior such as risk-taking behavior and furthermore suggests that hypoactivity in the right prefrontal cortex might serve as a dispositional indicator of lower regulatory abilities, which is expressed in greater risk-taking behavior.
The Irony of Harmony
Authors: Saguy Tamar , Tausch Nicole , Dovidio John F. , Pratto Felicia
Published: December 2008

Positive intergroup contact has been a guiding framework for research on reducing intergroup tension and for interventions aimed at that goal. We propose that beyond improving attitudes toward the out-group, positive contact affects disadvantaged-group members' perceptions of intergroup inequality in ways that can undermine their support for social change toward equality. In Study 1, participants were assigned to either high- or low-power experimental groups and then brought together to discuss either commonalities between the groups or intergroup differences. Commonality-focused contact, relative to difference-focused contact, produced heightened expectations for fair (i.e., egalitarian) out-group behavior among members of disadvantaged groups. These expectations, however, proved unrealistic when compared against the actions of members of the advantaged groups. Participants in Study 2 were Israeli Arabs (a disadvantaged minority) who reported the amount of positive contact they experienced with Jews. More positive intergroup contact was associated with increased perceptions of Jews as fair, which in turn predicted decreased support for social change. Implications for social change are considered.
On the Presumption of Evidentiary Independence
Authors: Hasel Lisa E. , Kassin Saul M.
Published: December 2008

A confession is potent evidence, persuasive to judges and juries. Is it possible that a confession can also affect other evidence? The present study tested the hypothesis that a confession will alter eyewitnesses' identification decisions. Two days after witnessing a staged theft and making an identification decision from a lineup that did not include the thief, participants were told that certain lineup members had confessed or denied guilt during a subsequent interrogation. Among those participants who had made a selection but were told that another lineup member confessed, 61% changed their identifications. Among those participants who had not made an identification, 50% went on to select the confessor when his identity was known. These findings challenge the presumption in law that different forms of evidence are independent and suggest an important overlooked mechanism by which innocent confessors are wrongfully convicted: Potentially exculpatory evidence is corrupted by a confession itself.
The “Instrumentality” Heuristic
Authors: Labroo Aparna A. , Kim Sara
Published: December 2008

The literature overwhelmingly demonstrates that feelings of ease are good and that objects that are easy to process are much liked. We propose, and demonstrate across three experiments, that this is not the case when people are pursuing a goal. This is because people pursuing a goal (e.g., “become kinder”) usually invest efforts in whichever means (e.g., donate to a particular charity) they perceive as most instrumental for attaining their goal. Consequently, in their minds there is a correspondence between instrumentality of a means and feelings of effort. This correspondence becomes reversed in people's minds during goal pursuit, and they also come to view an object that is associated with feelings of effort rather than ease as more instrumental for goal attainment and consequently more desirable. When an object is not a means to fulfill an accessible goal, or when goals relating to the means are not accessible, subjective feelings of ease improve evaluation, as found in previous research on ease of processing.
Physical and digital proximity: emerging ways of health care in face‐to‐face and telemonitoring of heart‐failure patients
Authors: Oudshoorn Nelly
Published: December 2008

The introduction of telehealth‐care technologies profoundly changes existing practices of care. This paper aims to enhance our understanding of these changes by providing a comparative study of health‐care services for heart‐failure patients based on face‐to‐face contacts in a policlinic (department of a health care facility treating outpatients) and remote consultations at a telehealth‐care centre. I will show how changes that take place when care moves from physical to virtual clinical encounters cannot be understood in terms of a replication of existing health‐care services. Instead, it is more useful to conceptualise these health‐care provisions as practices that create and value other kinds of care, incorporating different forms of proximity to patients. The physical proximity created at the policlinic facilitates contextualised, personalised care in which responsibilities for monitoring are delegated to nurses and patients and heart failure is constituted as an illness. The digital proximity that characterises the telehealth‐care centre supports individualised, immediate care in which responsibilities are largely delegated to technological devices and heart failure is constituted as a disease. A major policy implication of these differences is that telehealth‐care cannot simply replace physical consultations without changing the nature of health care.
Indeterminacy and technicality revisited: how medicine and nursing have responded to the evidence based movement
Authors: Traynor Michael
Published: December 2008

In 1970 sociologists Jamous and Peloille proposed that occupational work could be understood as a combination of technical activity and indeterminate judgement and that the professions were characterised by high levels of indeterminacy relative to technicality. They argued that groups with low status or on the fringes of powerful professional groups were more likely to promote technically based reform, whereas elites were likely to resist with assertions of indeterminacy. Subsequent writers claimed that their notion of the indeterminacy/technicality ratio was more useful in analysis of professional ideology than in examinations of work content. During the 1990s the evidence based movement exerted a strong influence within the healthcare professions. Medicine and nursing responded in ways that reflected their differing status; however, both reactions included assertions that evidence based practice (EBP) could not take into account the subtle expertise required in daily clinical decision making. This paper argues that Jamous and Peloille's theories about technical reform and professional elites can help to explain responses to EBP. EBP was initially promoted by a relatively low‐status speciality of medicine while nursing, as an emerging profession, has shown more enthusiasm for its activities being formalised in a technically based fashion.
‘Post antibiotic apocalypse’: discourses of mutation in narratives of MRSA
Authors: Brown Brian , Crawford Paul
Published: December 2008

In this paper we will consider the question of mutation as it is manifested in press coverage of MRSA in UK hospitals. This represents a fertile field of discourse which brings into focus issues relating to microbes, people and working practices as well as the concepts of risk and vulnerability. A regular feature of reporting has been the presence of explanations for drug resistance involving repeated random mutations of the microbe to achieve progressively greater resistance and versatility, largely through a Darwinian process which is ‘clever’ at overcoming human attempts at elimination. More recently a discourse has emerged which foregrounds also the vulnerability of patients who are very young, old or otherwise immunocompromised, or whose own genetic makeup might put them at risk from the microbe. The hospital is decentred as a source of infection, and attention is turned instead to nursing homes and gymnasia as sources of infection in the community. This latter development mitigates the responsibilities of hospitals and statutory healthcare providers and turns the risk back towards the individual as a responsible actor in an ecology of mutation.
Status incongruence revisited: associations with shame and mental wellbeing
Authors: Lundberg Johanna , Kristenson Margareta , Starrin Bengt
Published: December 2008

Status incongruence has been related to poor health and all‐cause mortality, and could be a growing public health problem due to changes in the labour market in later decades. Shaming experiences have been suggested as playing a part in the aetiology. The aim here was to study the risk for shaming experiences, pessimism, anxiety, depressive feelings, and poor mental wellbeing (as measured by the GHQ) with a special focus on shame, in four social status categories: negatively and positively incongruent individuals, and low‐status and high‐status congruent individuals. Data comprised 14,854 working men and women from a regional sample of randomly selected respondents, 18–79 years of age. Logistic regression was used to study differences in risk for negative emotional outcomes. Results showed that the negative incongruent category persisted as the group most at risk for all negative emotional outcomes (OR 1.5–1.9; p < 0.05–<0.001). When testing the risk for poor mental wellbeing among the status categories with and without shaming experiences, ORs for all groups with shaming experiences were elevated. Among groups without shame, only the negative incongruent category remained at risk (OR 2.7; p < 0.05) after adjustment. Negative incongruent status is associated with adverse emotional outcomes, among them shame, which is a previously unappreciated aspect of status incongruence.
Homocysteine, vitamin B12 and folic acid levels in psoriasis patients
Authors: Çakmak SK , Gül Ü , Kılıç C , Gönül M , Soylu S , Kılıç A
Published: December 2008

Background  Hyperhomocysteinaemia is a risk factor for atherosclerotic cardiovascular disease, stroke, peripheral arterial occlusive disease and venous thrombosis. An association between psoriasis and cardiovascular diseases has been reported.

Aim  The aim of our study was to examine serum homocysteine, folic acid and vitamin B12 levels in psoriasis patients.

Material and methods  We performed a cross‐sectional study in 70 consecutive outpatients with chronic plaque psoriasis and 70 age‐ and gender‐matched controls. Serum levels of homocysteine, vitamin B12 and folic acid levels were measured in both groups.

Results  Serum homocysteine, folic acid and vitamin B12 levels did not differ between patient and control groups. In psoriasis patients, homocysteine levels correlated directly with psoriasis severity as measured by psoriasis area and severity index. Serum homocysteine level inversely correlated with serum folic acid levels in the patient group.

Discussion  Homocysteine levels correlated with psoriasis area and severity index in the patient group, which shows the disease severity. The increase in cardiovascular mortality with the severity of psoriasis might be also due to the effects of homocysteine.

Conflicts of interest

None declared
European ancestry and cutaneous melanoma in Southern Brazil
Authors: Bakos L , Masiero NCMS , Bakos RM , Burttet RM , Wagner MB , Benzano D
Published: December 2008

Background  Similar to other countries, incidence and mortality rates for cutaneous melanoma (CM) are increasing in Brazil. Resulting from centuries of ethnic mixture, the skin of the Brazilian population presents all phototypes, being progressively lighter following the increase of the latitude toward the South, where the highest incidence of melanoma is observed. Studies from the United States and Argentina in whites suggest that European ancestry could represent an important risk factor for CM in those regions.

Methods  Questionnaires from a case‐control study involving 119 melanoma patients and 177 controls were reviewed for age, gender, phototype, sun exposure, photoprotection and ancestry. The patients reported the countries of ancestry of their grandparents. Data were tabulated and converted into scores that would reflect the proportion of ancestry for each country in individuals.

Results  Patients with German and Italian ancestry presented higher risk for CM [odds ratio (OR), 3.5; 95% confidence interval (95% CI), 1.8–6.7 and OR, 9.7; 95% CI, 3.9–24.2, respectively]. Conversely, Brazilian indigenous ancestry showed a protective effect for the development of the disease, with an OR of 0.16 (95% CI, 0.04–0.7).

Conclusions  Some European ancestries, especially German and Italian, seem to be associated to a higher risk of CM in this sample from Southern Brazil. On the other hand, Brazilian indigenous ancestry presented as a protection factor against developing the tumour.

Conflicts of interest

None declared
Results of a public awareness campaign in Morocco regarding the sun's deleterious effects
Authors: Meziane M , Ahid S , Azendour H , Ismaili N , Marcil T , Afifi Y , Senouci K , Abouqal R , Hassam B , Belgnaoui FZ
Published: December 2008

Objective  To investigate knowledge of the various sun radiation–related risks and awareness of photoprotection measures using a sample of the Moroccan population.

Methods  An investigation of prevalence, which was administered while a public awareness campaign on the sun's harmful effects, organized by the department of dermatology of Ibn Sina's hospital in Rabat, was running. The collection of the data was made on the basis of a questionnaire that was filled by the team of the doctors of the department. The logistic regression allowed to identify the explanatory factors for the prevalent knowledge and behaviours related to the subject in hand.

Results  Four hundred eleven subjects were included in the survey. The subjects' average age was 40 ± 10 years. Eighty‐four per cent were female. The analysis of the total score of knowledge related to the sunrays’ deleterious effects demonstrated low levels of knowledge among 160 participants (38.9%). Females were clearly more knowledgeable than the opposite sex (P = 0.003) and also those having a higher educational level (P = 0.006) scored high. The use of sunscreens was recognized by 52.8% of the patients and was associated with female gender and higher educational level.

Conclusion  Our study reports the results of the first public awareness campaign on the sun's deleterious effects on the Moroccan population, inclusive and relevant to all ages. Awareness of the sun's radiation‐related risks in a country as sunny as ours is low, whereas different measures of photoprotection are rather well known. Messages adapted to the characteristics of our population are a necessity.
CD28 T‐cell costimulatory molecule expression in pemphigus vulgaris
Authors: Alecu M , Ursaciuc C , Surcel M , Coman G , Ciotaru D , Dobre M
Published: December 2008

Background  CD28 superfamily of immune costimulatory molecules could play an important role in autotolerance control. CD28 costimulation seems to be necessary for regulatory T cell (Treg) activation and successive suppressive activities involved in autoimmunity protection. This study investigates CD28 expression, especially inducible costimulator fraction, on T lymphocytes in pemphigus vulgaris (PV) patients.

Methods  CD28 expression on T lymphocytes was assessed in 16 PV patients during acute attack. All patients and 10 healthy control subjects were tested for lymphocyte populations, T‐cell subpopulations (T‐CD4+, T‐CD8+), Treg and CD28 expression on T‐cell subpopulations.

Results  T, B and natural killer cells average values in PV patients were close to the control group values. Compared with control group, PV values showed lower Treg (2.2% compared with 4.7%), slightly decreased CD4+ CD28+ T cells (91% compared with 95%), higher CD4+ CD28− T cells (9% compared with 5%), decreased CD8+ CD28+ T cells (57% and 73%, respectively) and significantly enhanced CD8+ CD28− T cells (43% compared with 27%).

Conclusions  These data suggest that Treg‐mediated suppressor T‐cell effects could be diminished in PV, together with an abnormal or ineffective subsequent helper T‐cell suppression. CD28 high expression on helper T cells and low expression on suppressor T cells are arguments for a potential CD28 role in PV autoimmune response mechanism.

Conflicts of interest

None declared
Life satisfaction together with positive and negative aspects in Polish patients with systemic lupus erythematosus
Authors: Kulczycka L , Sysa‐Jedrzejowska A , Robak E
Published: December 2008

Purpose  To determinate satisfaction with life together with positive and negative emotions in SLE patients and correlate them with each other and with activity of the disease, duration of the disease and age of the patient.

Methods  The study was conducted on 83 SLE patients who fulfilled at least 4 out of 11 ACR criteria. Satisfaction with life was measured by the Satisfaction with Life Scale. Positive and negative aspects were assessed by the Positive and Negative Affects Schedule. Other data were collected from the patients at the same time.

Results  SLE patients presented reduced satisfaction with life. Duration of the disease, as well as age of the patients had an influence on it. Correlations between patients’ quality of life emotions and life's satisfaction were present.

Conclusions  SLE as a chronic, incurable and unpredictable disease has a great influence on patients’ life. The awareness of this may lead to better compliance and to develop a new strategy of therapy.

Conflicts of interest

None declared
Knockdown of m‐calpain increases survival of primary hippocampal neurons following NMDA excitotoxicity
Authors: Bevers Matthew B. , Lawrence Eric , Maronski Margaret , Starr Neasa , Amesquita Michael , Neumar Robert W.
Published: December 2008

The calpain family of cysteine proteases has a well‐established causal role in neuronal cell death following acute brain injury. However, the relative contribution of calpain isoforms to the various forms of injury has not been determined as available calpain inhibitors are not isoform‐specific. In this study, we evaluated the relative role of m‐calpain and μ‐calpain in a primary hippocampal neuron model of NMDA‐mediated excitotoxicity. Baseline mRNA expression for the catalytic subunit of m‐calpain (capn2 ) was found to be 50‐fold higher than for the μ‐calpain catalytic subunit (capn1) based on quantitative real‐time PCR. Adeno‐associated viral vectors designed to deliver short hairpin RNAs targeting capn1 or capn2 resulted in 60% and 90% knockdown of message respectively. Knockdown of capn2 but not capn1 increased neuronal survival after NMDA exposure at 21 days in vitro. Nuclear translocation of calpain substrates apoptosis inducing factor, p35/p25 and collapsin response mediator protein (CRMP) 2–4 was not detected after NMDA exposure in this model. However, nuclear translocation of CRMP‐1 was observed and was prevented by capn2 knockdown. These findings provide insight into potential mechanisms of calpain‐mediated neurodegeneration and have important implications for the development of isoform‐specific calpain inhibitor therapy.
AZD2184: a radioligand for sensitive detection of β‐amyloid deposits
Authors: Johnson Allan E. , Jeppsson Fredrik , Sandell Johan , Wensbo David , Neelissen Jan A. M. , Juréus Anders , Ström Peter , Norman Henrietta , Farde Lars , Svensson Samuel P. S.
Published: December 2008

The presence of β‐amyloid plaques in brain is a hallmark of Alzheimer’s disease (AD) and serves as a biomarker for confirmation of diagnosis postmortem. Positron emission tomography (PET) radioligands such as Pittsburgh compound B ([11C]‐2‐(3‐fluoro‐4‐methylamino‐phenyl)‐benzothiazol‐6‐ol) (PIB) binds selectively to β‐amyloid and are promising new tools supporting the clinical diagnoses of AD. In addition, such methodology may be useful for evaluation of new drugs aiming at reduction of amyloid plaque load. The objective of this study is to develop a new amyloid selective PET radioligand with higher signal‐to‐background ratio when compared with existing amyloid PET ligands. The lead compound, AZD2184, (2‐[6‐(methylamino)pyridin‐3‐yl]‐1,3‐benzothiazol‐6‐ol) was found to have high affinity for amyloid fibrils in vitro (Kd: 8.4 ± 1.0 nM). Two minutes after i.v. administration in rats, about 1% of the dose was in brain. In vitro autoradiography on cortical brain sections from amyloid‐beta precursor protein/presenilin 1 (APP/PS1) mice and AD patients showed that while [3H]AZD2184 and [3H]PIB are mutually displaceable, [3H]AZD2184 displays a higher signal‐to‐background ratio primarily by virtue of lower background binding levels. The ratio of binding ability in prefrontal cortex (high plaque load) to subcortical white matter (background) was 4.5 for [3H]AZD2184 and 0.8 for [3H]PIB at 1 nM. In adjacent cortical sections from APP/PS1 mouse as well as from AD cortical tissue, [3H]AZD2184 and antibodies to human β‐amyloid labeled identical structures. In vivo administration of [3H]AZD2184 to APP/PS1 mice further showed that [3H]AZD2184 labels amyloid deposits with low non‐specific background binding. Taken together, the pre‐clinical profile of AZD2184 in relation to the reference ligand PIB, suggests that 11C‐labeled AZD2184 is a potential radioligand for PET‐visualization of β‐amyloid deposits in the living human brain.
Signaling mechanisms of interferon gamma induced apoptosis in chromaffin cells: involvement of nNOS, iNOS, and NFκB
Authors: Pérez‐Rodríguez Rocío , Roncero Cesáreo , Oliván Ana María , González María Pilar , Oset‐Gasque María Jesús
Published: December 2008

Previous work of our group stated that exogenously added and endogenous nitric oxide (NO) generated by cytokines induce apoptosis in chromaffin cells. In this work, we investigate the specific regulation of the NO synthase (NOS) isoforms, inducible NOS (iNOS) and neuronal NOS (nNOS), and their particular participation in cell death induced by interferon gamma (IFNγ). Lipopolysaccharide (LPS) and IFNγ increase iNOS expression, with no effect on nNOS expression. On the other hand, dexamethasone increases basal nNOS expression but decreases LPS + IFNγ‐induced iNOS expression. IFNγ‐induced cell death was abolished by W‐1400, a specific iNOS inhibitor, but only partially by nNOS inhibitors [N‐ω‐propyl‐l‐arginine (N‐PLA), 3‐Bromo‐7‐nitroindazol (7‐NI),l‐methyl thiocitrulline andN‐methyll‐arginine], indicating the main iNOS participation in chromaffin cell death. IFNγ and LPS induce nuclear factor κB (NFκB) translocation to the nucleus, a process implicated in activation of iNOS expression, as inhibition of NFκB translocation, by SN50, decreased iNOS expression. In addition, IFNγ and LPS induce847Ser‐nNOS phosphorylation, inhibiting nNOS activity. Both processes, nNOS phosphorylation and iNOS expression induced by LPS + IFNγ, are regulated by Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) pathway, as IFNγ increases727STAT‐3 phosphorylation and specific inhibitors of JAK/STAT pathway, such as AG490, inhibited both processes. Taken together, these results support the hypothesis of an inactivating phosphorylation of nNOS by IFNγ, via JAK/STAT, in bovine chromaffin cells. Low NO concentrations achieved by this event, would activate NFκB translocation, increasing iNOS expression and generating, this last, high apoptotic NO concentrations.
The CREB/CRE transcriptional pathway: protection against oxidative stress‐mediated neuronal cell death
Authors: Lee Boyoung , Cao Ruifeng , Choi Yun‐Sik , Cho Hee‐Yeon , Rhee Alex D. , Hah Cyrus K. , Hoyt Kari R. , Obrietan Karl
Published: December 2008

Formation of reactive oxygen and nitrogen species is a precipitating event in an array of neuropathological conditions. In response to excessive reactive oxygen species (ROS) levels, transcriptionally dependent mechanisms drive the up‐regulation of ROS scavenging proteins which, in turn, limit the extent of brain damage. Here, we employed a transgenic approach in which cAMP‐response element binding protein (CREB)‐mediated transcription is repressed (via A‐CREB) to examine the contribution of the CREB/cAMP response element pathway to neuroprotection and its potential role in limiting ROS toxicity. Using the pilocarpine‐evoked repetitive seizure model, we detected a marked enhancement of cell death in A‐CREB transgenic mice. Paralleling this, there was a dramatic increase in tyrosine nitration (a marker of reactive species formation) in A‐CREB transgenic mice. In addition, inducible expression of peroxisome proliferator‐activated receptor gamma coactivator‐1α was diminished in A‐CREB transgenic mice, as was activity of complex I of the mitochondrial electron transport chain. Finally, the neuroprotective effect of brain‐derived neurotrophic factor (BDNF) against ROS‐mediated cell death was abrogated by disruption of CREB‐mediated transcription. Together, these data both extend our understanding of CREB functionality and providein vivovalidation for a model in which CREB functions as a pivotal upstream integrator of neuroprotective signaling against ROS‐mediated cell death.
Seeing the forest with the leaves – clues to canopy placement from leaf fossil size and venation characteristics
Authors: BOYCE C. K.
Published: December 2008

Although a variety of leaf characteristics appear to be induced by light environment during development, analysis of ontogenetic changes in living broad leaved trees has suggested that a number of other traits also lumped into the classic ‘sun’ versus ‘shade’ morphological distinctions, including leaf size, shape, and vein density, are instead controlled largely by local hydraulic environment within the tree canopy. The regularity in how these traits vary with canopy placement suggests a method for addressing a classic paleobotanical quandary: the stature of the source plant – from herb or shrub to canopy tree – is typically unknown for leaf fossils. The study of Ginkgo here complements previous work on Quercus that indicated that leaves throughout the crown are identical in size and venation at the time of bud break and that morphological adaptation to the local microenvironment takes place largely during the expansion phase after the determination of the vascular architecture is complete. Hence, variation in vein density does not reflect differential vein production so much as the distortion of similar vein networks over different final surface areas driven by variation in local hydraulic supply during expansion. Unlike the diffusely growing leaves of the angiosperm, Quercus, the marginally growing leaves of Ginkgo do show some potential for differential vein production, but expansion effects still dominate. The approach suggested here may prove useful for assessing the likelihood that two distinct fossil morphospecies actually represent leaves of the same plant and to gather information concerning canopy structure from disarticulated leaves.
Morphology and wall ultrastructure of leiosphaeric and acanthomorphic acritarchs from the Ediacaran of Australia
Authors: WILLMAN S.
Published: December 2008

Acritarchs are a group of organic‐walled microfossils with unknown biological affinities. The wall ultrastructure of the unornamented, smooth Leiosphaeridia sp. and the acanthomorphic Gyalosphaeridium pulchrum from the Ediacaran Dey Dey Mudstone in the Officer Basin, South Australia, was studied by use of transmission and scanning electron microscopy, and transmitted light microscopy. The study of the ultrastructure reveals a complexity in the cell wall not seen in prokaryotes. Wall ultrastructures range from single‐layered to three‐ or four‐layered and from homogeneous to porous. Acritarchs with different wall ultrastructures may be different organisms, but may also reflect different stages in a life cycle. In this paper I review previous ultrastructure studies and discuss possible algal and metazoan affinities for the specimens studied herein.
Preliminary characterization and biological reduction of putative biogenic iron oxides (BIOS) from the Tonga‐Kermadec Arc, southwest Pacific Ocean
Authors: LANGLEY S. , IGRIC P. , TAKAHASHI Y. , SAKAI Y. , FORTIN D. , HANNINGTON M. D. , SCHWARZ‐SCHAMPERA U.
Published: December 2008

Sediment samples were obtained from areas of diffuse hydrothermal venting along the seabed in the Tonga sector of the Tonga‐Kermadec Arc, southwest Pacific Ocean. Sediments from Volcano 1 and Volcano 19 were analyzed by X‐ray diffraction (XRD) and found to be composed primarily of the iron oxyhydroxide mineral, two‐line ferrihydrite. XRD also suggested the possible presence of minor amounts of more ordered iron (hydr)oxides (including six‐line ferrihydrite, goethite/lepidocrocite and magnetite) in the biogenic iron oxides (BIOS) from Volcano 1; however, Mössbauer spectroscopy failed to detect any mineral phases more crystalline than two‐line ferrihydrite. The minerals were precipitated on the surfaces of abundant filamentous microbial structures. Morphologically, some of these structures were similar in appearance to the known iron‐oxidizing genus Mariprofundus spp., suggesting that the sediments are composed of biogenic iron oxides. At Volcano 19, an areally extensive, active vent field, the microbial cells appeared to be responsible for the formation of cohesive chimney‐like structures of iron oxyhydroxide, 2–3 m in height, whereas at Volcano 1, an older vent field, no chimney‐like structures were apparent. Iron reduction of the sediment material (i.e. BIOS) by Shewanella putrefaciens CN32 was measured, in vitro, as the ratio of [total Fe(II)]:[total Fe]. From this parameter, reduction rates were calculated for Volcano 1 BIOS (0.0521 day−1), Volcano 19 BIOS (0.0473 day−1), and hydrous ferric oxide, a synthetic two‐line ferrihydrite (0.0224 day−1). Sediments from both BIOS sites were more easily reduced than synthetic ferrihydrite, which suggests that the decrease in effective surface area of the minerals within the sediments (due to the presence of the organic component) does not inhibit subsequent microbial reduction. These results indicate that natural, marine BIOS are easily reduced in the presence of dissimilatory iron‐reducing bacteria, and that the use of common synthetic iron minerals to model their reduction may lead to a significant underestimation of their biological reactivity.
Biomineralization by photosynthetic organisms: Evidence of coevolution of the organisms and their environment?
Authors: RAVEN J. A. , GIORDANO M.
Published: December 2008

Biomineralization is widespread among photosynthetic organisms in the ocean, in inland waters and on land. The most quantitatively important biogeochemical role of land plants today in biomineralization is silica deposition in vascular plants, especially grasses. Terrestrial plants also increase the rate of weathering, providing the soluble substrates for biomineralization on land and in water bodies, a role that has had global biogeochemical impacts since the Devonian. The dominant photosynthetic biomineralizers in today's ocean are diatoms and radiolarians depositing silica and coccolithophores and foraminifera depositing calcium carbonate. Abiotic precipitation of silica from supersaturated seawater in the Precambrian preceded intracellular silicification dominated by sponges, then radiolarians and finally diatoms, with successive declines in the silicic acid concentration in the surface ocean, resulting in some decreases in the extent of silicification and, probably, increases in the silicic acid affinity of the active influx mechanisms. Calcium and bicarbonate concentrations in the surface ocean have generally been supersaturating with respect to the three common calcium carbonate biominerals through geological time, allowing external calcification as well as calcification in compartments within cells or organisms. The forms of calcium carbonate in biominerals, and presumably the evolution of the organisms that produce them, have been influenced by abiotic variations in calcium and magnesium concentrations in seawater, and calcium carbonate deposition has probably also been influenced by carbon dioxide concentration whose variations are in part biologically determined. Overall, there has been less biological feedback on the availability of substrates for calcification than is the case for silicification.
Redox control of N:P ratios in aquatic ecosystems
Authors: QUAN T. M. , FALKOWSKI P. G.
Published: December 2008

The ratio of dissolved fixed inorganic nitrogen to soluble inorganic phosphate (N:P) in the ocean interior is relatively constant, averaging ~16 : 1 by atoms. In contrast, the ratio of these two elements spans more than six orders of magnitude in lakes and other aquatic environments. To understand the factors influencing N:P ratios in aquatic environments, we analyzed 111 observational datasets derived from 35 water bodies, ranging from small lakes to ocean basins. Our results reveal that N:P ratios are highly correlated with the concentration of dissolved O2 below ~100 µmol L−1. At higher concentrations of O2, N:P ratios are highly variable and not correlated with O2; however, the coefficient of variation in N:P ratios is strongly related to the size of the water body. Hence, classical Redfield ratios observed in the ocean are anomalous; this specific elemental stoichiometry emerges not only as a consequence of the elemental ratio of the sinking flux of organic matter, but also as a result of the size of the basins and their ventilation. We propose that the link between N:P ratios, basin size and oxygen levels, along with the previously determined relationship between sedimentary δ15N and oxygen, can be used to infer historical N:P ratios for any water body.
Spatiotemporal distribution of microbial communities in a coastal, sandy aquifer system (Doñana, SW Spain)
Authors: VELASCO AYUSO S. , GUERRERO M. C. , MONTES C. , LÓPEZ‐ARCHILLA A. I.
Published: December 2008

The aquifer system of Doñana (SW Spain) represents the most important freshwater source in the Doñana Natural Area. Its spatiotemporal dynamics favours the hydrological connection between surface and subsurface ecosystems, and promotes matter fluxes among the different terrestrial and aquatic systems present here. This aquifer has been intensively studied from a hydrogeological point of view but little is known from an ecological perspective. In order to understand the ecological roles played by microbial communities in this system, we conducted a long‐term seasonal study of bacterial abundance, cell biomass, bacterial biomass and functional activities over a 2‐year period. Bacterial abundance ranged between 2.11 ± 1.79 × 105 and 8.58 ± 6.99 × 107 bacteria mL−1 groundwater, average cell biomass was estimated to be 77.01 ± 31.56 fgC and bacterial biomass varied between 8.99 ± 4.10 × 10−2 and 5.65 ± 0.70 µgC mL−1. Iron‐related bacteria showed the highest activities among the functional groups studied. Moreover, among the variables that usually control spatial distributions of microbial communities in aquifer systems, depth did not have a relevant effect on this aquifer, at least in the range of depths studied, but grain size, probably due to its direct effects on hydrogeological parameters, such as permeability or porosity, appeared to exert moderate control, principally in terms of bacterial abundance. Finally, significant seasonal differences in the means of these microbiological variables were also observed; temperature seems to be the main factor controlling the temporal distribution of microbial communities in this aquifer system.
ANALYSIS OF FIRST MILLENNIUMbcGLASS VESSELS AND BEADS FROM THE PICHVNARI NECROPOLIS, GEORGIA*
Authors: SHORTLAND A. J. , SCHROEDER H.
Published: December 2008

The Pichvnari necropolis on the Black Sea coast of Georgia lies in an area known in the late first millennium as ‘Colchis’, on part of the trade route leading to the Orient. The burials of the necropolis date to the late fifth centurybcand frequently contain grave goods, including extremely well‐preserved polychrome glass beads and core‐formed vessels. This paper presents a study of these vessels both stylistically and archaeologically and using SEM–WDS and LA–ICPMS. It reveals that the vessels have compositional differences that may point to multiple manufacturing sites. One of the vessels appears stylistically unique and may exhibit one of the earliest uses of manganese as a decolorizer. Major and minor element data for the vessels suggest that they may belong to the same ‘Levantine’ group as many Roman glass objects, suggesting that a source of sand on the coast of the Levant could have been used in their production. The beads clearly show glass with both natron‐ and plant ash‐based flux with distinct rare earth compositions, showing multiple sites of production, some of which were probably either in the Middle East or the Indian subcontinent.