bluuebunny/crossref_metadata_2025 huggingface dataset:
Lifetime reproductive success and sexual selection theory
Authors: Koenig Walter D.
Published: September 2008

This chapter summarizes studies of lifetime reproductive success (LRS) conducted on odonates. Such studies have focused on many characters, but have typically concluded that survivorship — the main component of natural selection, is more important than mating efficiency — a primary component of sexual selection, in determining LRS. They have also frequently found that environmental factors are important and that selection and the opportunity for selection vary considerably depending on density, sex ratio, and community composition. LRS studies have been most successful when focused on specific traits and when complemented by experimental manipulations. Progress in understanding the current actions of natural and sexual selection is thus most likely to involve long-term LRS work combined with experimental or comparative approaches. Particularly desirable are studies that incorporate the larval stage in fitness calculations, perform parentage analyses to determine realized fitness, and consider the role of non-breeding behaviours such as foraging efficiency.
Fitness landscapes, mortality schedules, and mating systems
Authors: Anholt Bradley R.
Published: September 2008

Acquiring the resources for reproduction comes at the risk of death. After emergence, females of most odonate species gain more mass than males and concomitantly suffer higher mortality rates. Differences in adult mortality rates affect the operational sex ratio. The expected number of future matings for males affects whether males should defend territories or contact guard mates. Where females gain much more mass than males and suffer higher mortality as a result, a male with a mate has a very low expectation of additional matings and should contact guard a mate to maximize reproductive success. When the operational sex ratio is less male-biased, a male with a mate may have additional opportunities to mate and can maximize his reproductive success by territorial behaviour.
Testing hypotheses about parasite-mediated selection using odonate hosts
Authors: Forbes Mark R. , Robb Tonia
Published: September 2008

Parasites are thought to select for host traits, such as elaborate ornaments and intricate immune systems. Dragonflies have proven useful hosts for studying parasite-mediated selection. This chapter summarizes whether parasites exert fitness costs on their dragonfly hosts and affect signals and the mating success of males. It also reviews determinants of resistance against ectoparasitic mites, which is present in many dragonfly species and introduces recent work suggesting that host gender and age influence immunological responses to bacterial and artificial challenges. The chapter highlights that the likelihood of demonstrating parasite-mediated selection might depend on whether or not the species being considered is a generalist parasite. New ideas on elucidating how dragonfly prey species should deal with threats from multiple enemies, such as predators and parasites, are considered.
Cryptic female choice and sexual conflict
Authors: Córdoba-Aguilar Alex , Cordero-Rivera Adolfo
Published: September 2008

Females may choose their male mates. However, both sexes may engage in a kind of dispute not to be coerced into mating (for females) and to be chosen (for males). These two hypotheses (called female choice and sexual conflict, respectively) are currently in vogue in studies of sexual reproduction. This chapter highlights some instances where both can be tested in odonates. These instances are: during copula invitation by males, for the duration of copulation, and during the male post-copulatory displays preceding and during oviposition. There are four other aspects that may be investigated to see the prevalence of each hypothesis: the differences of genitalic diversity across populations, the genitalic complexity at the multiple species level, the female benefits when mating with ‘attractive’ males, and the costs to evade superfluous matings.
Territoriality in odonates
Authors: Suhonen Jukka , Rantala Markus J. , Honkavaara Johanna
Published: September 2008

This chapter discusses causes and consequences of territorial behaviour in odonates. In territorial species, males may use two mating tactics or strategies that may be environmentally or genetically determined: territoriality and non-territoriality. The tactic a male exhibits in each particular case is determined by the cost-benefit ratio of territorial and non-territorial behaviours. The main benefit of territoriality is increased access to females, and the costs may accumulate due to e.g., predation, injuries, and/or energy loss due to territorial contests. Moreover, density of both males and females as well as sex-ratio at breeding sites both contribute to the costs and benefits of each tactic. Interspecific aggression by heterospecific males may also influence the profitability of these tactics.
The evolution of sex-limited colour polymorphism
Authors: Gossum Hans Van , Sherratt Tom N. , Cordero-Rivera Adolfo
Published: September 2008

Species that exhibit genetic colour polymorphism are ideal for studying the micro-evolutionary forces that maintain genetic variation in nature. One very intriguing polymorphism is the coexistence of several discrete morphs within only one sex, with one morph often resembling the opposite sex in colour and sometimes behaviour. In males, this resemblance often allows access to receptive females, while in females the polymorphism appears related to avoiding excessive male sexual harassment. One might wonder why natural selection does not simply give rise to a single best male and female type for each species. The phenomenon of sex-limited polymorphisms provides an important opportunity to test contemporary ideas relating to sexual selection and sexual conflict, and the diversity of polymorphisms that have arisen in odonates clearly offers one of the best natural systems for among species and population comparative research.
Dragonfly flight performance: a model system for biomechanics, physiological genetics, and animal competitive behaviour
Authors: Marden James H.
Published: September 2008

Adult dragonflies are heavily dependent on their flight muscles and flight ability for nearly all of their adult activities. This chapter reviews research that presents dragonflies as model organisms for examining mechanisms that underlie variation in flight performance within and between species, molecular mechanisms by which muscle performance is adjusted within individuals, and how these physiological traits affect territorial and mating success. Results of these studies in dragonflies have provided fundamental new knowledge that informs the theoretical bases of a number of fields: biomechanics of animal locomotion, physiological genetics, and game theory approaches to animal contests. New insights that cross the boundaries of these disparate fields demonstrate the payoff for performing integrative research.
Evolution, diversification, and mechanics of dragonfly wings
Authors: Wootton Robin J. , Newman David J.S.
Published: September 2008

This chapter shows how the patterns of evolution and diversification of odonatoids, and by implication those of other flight-active taxa can be illuminated by studying their flight mechanics. The relationships between flight capabilities and wing and body design are discussed; and the functional significance of familiar wing characters and character states are investigated and compared in a range of extant and extinct odonates, using simple physical models. Convergence in wing shape and in some other characters is shown to be widespread, reflecting similarities in flight behaviour and performance in different taxa throughout the long history of the Superorder. Anagenesis — evolutionary ‘improvement’ — is also widely recognizable. Three important areas for future research are identified: detailed comparative investigations of flight performance; comparative morphometric analysis of functionally interpretable wing and body characters; and detailed Finite Element modelling of selected wing characters, rather than superficial analyses of complete wings.
Ballistic Phase of Self-Interacting Random Walks
Authors: Ioffe Dmitry , Velenik Yvan
Published: September 2008

The chapter presents a unified approach to a study of ballistic phase for a large family of self-interacting random walks with a drift and self-interacting polymers with an external stretching force. The approach is based on a recent version of the Ornstein–Zernike theory. It leads to local limit results for various observables (e.g. displacement of the end-point or number of hits of a fixed finite pattern) on paths of n-step walks (polymers) on all possible deviation scales from CLT to LD. The class of models, which display ballistic phase in the ‘universality class’ discussed in the chapter, includes self-avoiding walks, Domb–Joyce model, random walks in an annealed random potential, reinforced polymers, and weakly reinforced random walks.
Stochastic Homogenization and Energy of Infinite Sets of Points
Authors: Blanc Xavier
Published: September 2008

This chapter presents, in a synthetic way, a series of recent works by X. Blanc, C. Le Bris, and P-L. Lions on homogenization of an elliptic partial differential equation under certain periodic or random assumptions. The coefficients are non-constant but are a stationary random deformation of a periodic set of coefficients; a limit is taken where the period (in d-space) of the periodicity shrinks to zero. The chapter also describes related work on average energies of nonperiodic infinite sets of points.
Applications of the Lace Expansion to Statistical-Mechanical Models
Authors: Sakai Akira
Published: September 2008

Synergetics is a common feature in interesting statistical-mechanical problems. One of the most important examples of synergetics is the emergence of a second-order phase transition and critical behaviour. It is rich and still far from fully understood. The reason why it is so difficult is due to the increase to infinity of the number of strongly correlated variables in the vicinity of the critical point. For example, the Ising model, which is a model for magnets, exhibits critical behaviour as the temperature comes closer to its critical value; the closer the temperature is to criticality, the more spin variables cooperate with each other to attain the global magnetization. In this regime, neither standard probability theory for independent random variables nor naive perturbation techniques work. The lace expansion, which is the topic of this article, is currently one of the few approaches to rigorous investigation of critical behaviour for various statistical-mechanical models. The chapter summarizes some of the most intriguing lace-expansion results for self-avoiding walk (SAW), percolation, and the Ising model.
Large Deviations for Empirical Cycle Counts of Integer Partitions and Their Relation to Systems of Bosons
Authors: Adams Stefan
Published: September 2008

Motivated by the Bose gas, this chapter introduces certain combinatorial structures. It analyses the asymptotic behaviour of empirical shape measures and of empirical path measures of N Brownian motions with large deviations techniques. The rate functions are given as variational problems that are analysed. A symmetrized system of Brownian motions is highly correlated and has to be formulated such that standard techniques can be applied. The chapter reviews a novel spatial and a novel cycle structure approach for the symmetrized distributions of the empirical path measures. The cycle structure leads to a proof of a phase transition in the mean path measure.
Interacting Brownian Motions and the Gross-Pitaevskii Formula
Authors: Adams Stefan , König Wolfgang
Published: September 2008

Bose–Einstein condensation predicts that, under certain conditions (in particular extremely low temperature), all particles will condense into one state. Some of the physical background is surveyed in this chapter. The Gross–Pitaevskii approximation for dilute systems is also discussed. Variational problems appear here naturally, as the quantum mechanical ground state is of interest. In connection with positive temperature, related probabilistic models, based on interacting Brownian motions in a trapping potential, are introduced. Again, large deviation techniques are used to determine the mean occupation measure, both for vanishing temperature and large particle number.
Effective Theories for Ostwald Ripening
Authors: Niethammer Barbara
Published: September 2008

This chapter discusses the derivation and analysis of reduced models for a coarsening process known as Ostwald ripening, which is a paradigm for statistical self-similarity in coarsening systems. The underlying physical phenomenon appears in the late stage of phase transitions, when—due to a change in temperature or pressure for example — the energy of the underlying system becomes nonconvex and prefers two different phases of the material. Consequently a homogeneous mixture is unstable and, in order to minimze the energy, it separates into the two stable phases. Typical examples are the condensation of liquid droplets in a supersaturated vapur and phase separation in binary alloys after rapid cooling.
Switching Paths for Ising Models with Long-Range Interaction
Authors: Dirr Nicolas
Published: September 2008

The chapter discusses a multiscale model for a two-phases material. The model is a stochastic process on the finest scale. The effective behaviour on larger scales is governed by deterministic nonlinear evolution equations. Due to the stochasticity on the finest scale, deviations from these limit evolution laws can happen with small probability. The chapter describes the most likely among those deviations in two situations: (i) the switching from one stable equilibrium of the evolution equation to another one, (ii) enforced, fast motion on a manifold of stationary solutions. This chapter is based on joint work with Giovanni Bellettini, Anna DeMasi and Errico Presutti.
Nucleation and Droplet Growth as a Stochastic Process
Authors: Penrose Oliver
Published: September 2008

This chapter proposes a stochastic differential equation as the putative limit for a birth-and-death Markov chain model for the fluctuating size of a droplet, in a fluid, that is metastable with respect to nucleation of a new phase. This chapter uses the large deviations theory of Freidlin and Wentzell to give a variational analysis of the path properties of the solution to this stochastic differential equation, relating these results to the classical theory of Becker and Doring.
On the Stochastic Burgers Equation and Some Applications to Turbulence and Astrophysics
Authors: Neate A.D. , Truman A.
Published: September 2008

This chapter summarises a selection of results on the inviscid limit of the stochastic Burgers equation emphasising geometric properties of the caustic, Maxwell set and Hamilton-Jacobi level surfaces and relating these results to a discussion of stochastic turbulence. It shows that for small viscosities there exists a vortex filament structure near to the Maxwell set. It is discussed how this vorticity is directly related to the adhesion model for the evolution of the early universe, and new explicit formulas for the distribution of mass within the shock are included.
Liquid Crystals and Harmonic Maps in Polyhedral Domains
Authors: Majumdar Apala , Robbins Jonathan , Zyskin Maxim
Published: September 2008

This chapter is concerned with harmonic maps from a polyhedron to the unit two-sphere, which provide a model of nematic liquid crystals in bistable displays. This chapter looks at the Dirichlet energy of homo-topy classes of such harmonic maps, subject to tangent boundary conditions, and investigate lower and upper bounds for this Dirichlet energy on each homotopy class; local minimisers of this energy correspond to equilibrium and metastable configurations. A lower bound for the infimum Dirichlet energy for a given homotopy class is obtained as a sum of minimal connections between fractional defects at the vertices. In certain cases, this lower bound can be improved. For a rectangular prism, upper bounds are obtained from locally conformal solutions of the Euler-Lagrange equations, with the ratio of the upper and lower bounds bounded independently of homotopy type.
Biography and the Question of Literature in France
Authors: Jefferson Ann
Published: September 2008

This book explores the relations between literature and biography in France by tracing their history since the emergence of the two terms during the 18th century. This is when term ‘biographie’ first saw the light of day in the French language, and the word ‘littérature’ began to acquire its modern sense of writing marked by an aesthetic character. Arguing that the ‘idea of literature’ is inherently open to revision and contestation, the book examines the way in which biographically orientated texts have been engaged in turning literature into a question about its own definition. At the same time, it tracks the evolving forms of biographical writing in French culture, and proposes a reappraisal of biography that takes account not only of its forms, but also of its functions. The capacity of biography to intervene in debates about definitions of the literary argues for the need to consider this functional dimension of biographical writing. Although the study has important theoretical implications as regards both biography and the literary, it is intended first and foremost as a history, offering an account of the development of French literature through a dual focus on the question of literature and its relations with biography, and tracing the changing ideas about literature and chronicling the different forms taken by biography in the period. It includes readings of major authors and texts in the light of these concerns, from Rousseau to the ‘life-writing’ of contemporary authors such as Michon and Roubaud. Other authors discussed include Mme de Staël, Victor Hugo, Sainte-Beuve, Barbey d'Aurevilly, Baudelaire, Nerval, Mallarmé, Schwob, Proust, Gide, Leiris, Sartre, Genet, Barthes, and Laporte.
Contrasting response to Pleistocene climate change by ground-living and arborealMandarinasnails from the oceanic Hahajima archipelago
Authors: Davison Angus , Chiba Satoshi
Published: September 2008

While the genetic impact of Pleistocene climate change on temperate species has been well characterized, especially in Europe and North America, an effect on the diversification of species on oceanic islands has been less well studied. This is perhaps a surprising observation given the traditional and continuing contribution of island species (e.g. Darwin's finches,Partulasnails, Lord Howe Island palms) to understand speciation. Here, we combine mitochondrial and microsatellite data from the ground-living and arborealMandarinasnails of the oceanic, subtropical Hahajima archipelago (Ogasawara, colloquially ‘Galápagos of the Orient’) to enable a comparative approach to understand the impact of the Pleistocene glaciations on their phylogeography. Prior work suggested that several narrowly divergent, ground-living species pairs ofMandarinapopulations on the outlying islands, as well as the low-lying southern and central parts of Hahajima, probably underwent bottlenecks and subsequent expansions during the recent Pleistocene. Here, the most striking finding is that largely arboreal species have deeply divergent, geographically restricted mitochondrial lineages, in contrast to a census size that is at least an order of magnitude lower than ground-living snails. As populations of both types are highly polymorphic at microsatellite loci, the systematic difference at the mitochondrial locus probably indicates a contrasting effect of the Pleistocene climate cycles on the two groups. We speculate that this may have partly come about owing to a reduced efficacy of natural selection on the more greatly structured populations of arboreal snails. If so, then a prediction is that the genome of other snails, or other species with limited mobility, will show a similar response to the Pleistocene climate cycles.
The age and origin of the Pacific islands: a geological overview
Authors: Neall Vincent E , Trewick Steven A
Published: September 2008

The Pacific Ocean evolved from the Panthalassic Ocean that was first formed
ca
750 Ma with the rifting apart of Rodinia. By 160 Ma, the first ocean floor ascribed to the current Pacific plate was produced to the west of a spreading centre in the central Pacific, ultimately growing to become the largest oceanic plate on the Earth. The current Nazca, Cocos and Juan de Fuca (Gorda) plates were initially one plate, produced to the east of the original spreading centre before becoming split into three. The islands of the Pacific have originated as: linear chains of volcanic islands on the above plates either by mantle plume or propagating fracture origin, atolls, uplifted coralline reefs, fragments of continental crust, obducted portions of adjoining lithospheric plates and islands resulting from subduction along convergent plate margins. Out of the 11 linear volcanic chains identified, each is briefly described and its history summarized. The geology of 10 exemplar archipelagos (Japan, Izu-Bonin, Palau, Solomons, Fiji, New Caledonia, New Zealand, Society, Galápagos and Hawaii) is then discussed in detail.
Effects of category learning on the stimulus selectivity of macaque inferior temporal neurons
Authors: De Baene Wouter , Ons Bart , Wagemans Johan , Vogels Rufin
Published: September 2008

Primates can learn to categorize complex shapes, but as yet it is unclear how this categorization learning affects the representation of shape in visual cortex. Previous studies that have examined the effect of categorization learning on shape representation in the macaque inferior temporal (IT) cortex have produced diverse and conflicting results that are difficult to interpret owing to inadequacies in design. The present study overcomes these issues by recording IT responses before and after categorization learning. We used parameterized shapes that varied along two shape dimensions. Monkeys were extensively trained to categorize the shapes along one of the two dimensions. Unlike previous studies, our paradigm counterbalanced the relevant categorization dimension across animals. We found that categorization learning increased selectivity specifically for the category-relevant stimulus dimension (i.e., an expanded representation of the trained dimension), and that the ratio of within-category response similarities to between-category response similarities increased for the relevant dimension (i.e., category tuning). These small effects were only evident when the learned category-related effects were disentangled from the prelearned stimulus selectivity. These results suggest that shape-categorization learning can induce minor category-related changes in the shape tuning of IT neurons in adults, suggesting that learned, category-related changes in neuronal response mainly occur downstream from IT.
Post-retrieval β-adrenergic receptor blockade: Effects on extinction and reconsolidation of cocaine-cue memories
Authors: Fricks-Gleason Ashley N. , Marshall John F.
Published: September 2008

Contexts and discrete cues associated with drug-taking are often responsible for relapse among addicts. Animal models have shown that interference with the reconsolidation of drug-cue memories can reduce seeking of drugs or drug-paired stimuli. One such model is conditioned place preference (CPP) in which an animal is trained to associate a particular environment with the rewarding effects of a drug. Previous work from this laboratory has shown that intra-nucleus accumbens core infusions of a MEK inhibitor can interfere with reconsolidation of these drug-cue memories. A question that remains is whether post-retrieval drug effects on subsequent memories represent an interference with reconsolidation processes or rather a facilitation of extinction. In this experiment, we explore the effect of post-retrieval injections of propranolol, a β-adrenergic receptor antagonist, on reconsolidation and extinction of cocaine CPP. After acquisition of cocaine CPP, animals were given post-retrieval propranolol injections once or each day during a protocol of unreinforced preference tests, until the animals showed no preference for the previously cocaine-paired environment. Following a cocaine priming injection, the animals that received daily post-test propranolol injections did not reinstate their preference for the drug-paired side. In contrast, a single post-retrieval propranolol injection followed by multiple days of unreinforced preference tests failed to blunt subsequent cocaine reinstatement of the memory. These data suggest that daily post-retrieval systemic injections of propranolol decrease the conditioned preference by interfering with reconsolidation of the memory for the association between the drug-paired side and the reinforcing effects of the drug, rather than facilitating new extinction learning.
Yohimbine impairs extinction of cocaine-conditioned place preference in an α2-adrenergic receptor independent process
Authors: Davis Adeola R. , Shields Angela D. , Brigman Jonathan L. , Norcross Maxine , McElligott Zoe A. , Holmes Andrew , Winder Danny G.
Published: September 2008

Extinction, a form of learning that has the ability to reshape learned behavior based on new experiences, has been heavily studied utilizing fear learning paradigms. Mechanisms underlying extinction of positive-valence associations, such as drug self-administration and place preference, are poorly understood yet may have important relevance to addiction treatment. Data suggest a major role for the noradrenergic system in extinction of fear-based learning. Employing both pharmacological and genetic approaches, we investigated the role of the α2-adrenergic receptor (α2-AR) in extinction of cocaine-conditioned place preference (CPP) and glutamatergic transmission in the bed nucleus of the stria terminalis (BNST). We found that pre-extinction systemic treatment with the α2-AR antagonist yohimbine impaired cocaine CPP extinction in C57BL/6J mice, an effect that was not mimicked by the more selective α2-AR antagonist, atipamezole. Moreover, α2A-AR knockout mice exhibited similar cocaine CPP extinction and exacerbated extinction impairing effects of yohimbine. Using acute brain slices and electrophysiological approaches, we found that yohimbine produces a slowly evolving depression of glutamatergic transmission in the BNST that was not mimicked by atipamezole. Further, this action was extant in slices from α2A-AR knockout mice. Our data strongly suggest that extinction-modifying effects of yohimbine are unlikely to be due to actions at α2A-ARs.
Distinct contributions of the basolateral amygdala and the medial prefrontal cortex to learning and relearning extinction of context conditioned fear
Authors: Laurent Vincent , Westbrook R. Frederick
Published: September 2008

We studied the roles of the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC) in learning and relearning to inhibit context conditioned fear (freezing) in extinction. In Experiment 1, pre-extinction BLA infusion of the NMDA receptor (NMDAr) antagonist, ifenprodil, impaired the development and retention of inhibition but post-extinction infusion spared retention. Pre-extinction infusion of the GABAA agonist, muscimol, depressed freezing and impaired retention as did post-extinction infusion. In Experiment 2, pre-extinction mPFC infusion of ifenprodil spared the development of inhibition whereas muscimol depressed freezing. Both impaired retention when infused pre- or post-extinction. Thus, the development of inhibition involves NMDAr activation in the BLA, whereas its consolidation involves both NMDAr activation in the mPFC and NMDAr-independent mechanisms in the BLA. In Experiment 3, BLA infusion of ifenprodil impaired relearning and retention of inhibition when infused before but did not impair retention when infused after re-extinction. BLA infusion of muscimol depressed freezing but did not impair retention when infused before or after re-extinction. In Experiment 4, mPFC infusion of ifenprodil impaired relearning when infused before re-extinction, whereas muscimol depressed responses. Both drugs impaired retention when infused into the mPFC before or after re-extinction. Thus, relearning to inhibit fear responses involves NMDAr activation in both the BLA and mPFC and consolidation of the inhibitory memory involves NMDAr activation in the mPFC. However, relearning and consolidation occur in the absence of neuronal activity within the BLA. We propose that NMDAr in the mPFC supports relearning inhibition when the BLA is inactivated.
Distributed learning enhances relational memory consolidation
Authors: Litman Leib , Davachi Lila
Published: September 2008

It has long been known that distributed learning (DL) provides a mnemonic advantage over massed learning (ML). However, the underlying mechanisms that drive this robust mnemonic effect remain largely unknown. In two experiments, we show that DL across a 24 hr interval does not enhance immediate memory performance but instead slows the rate of forgetting relative to ML. Furthermore, we demonstrate that this savings in forgetting is specific to relational, but not item, memory. In the context of extant theories and knowledge of memory consolidation, these results suggest that an important mechanism underlying the mnemonic benefit of DL is enhanced memory consolidation. We speculate that synaptic strengthening mechanisms supporting long-term memory consolidation may be differentially mediated by the spacing of memory reactivation. These findings have broad implications for the scientific study of episodic memory consolidation and, more generally, for educational curriculum development and policy.
Neonatal odor-shock conditioning alters the neural network involved in odor fear learning at adulthood
Authors: Sevelinges Yannick , Sullivan Regina M. , Messaoudi Belkacem , Mouly Anne-Marie
Published: September 2008

Adult learning and memory functions are strongly dependent on neonatal experiences. We recently showed that neonatal odor-shock learning attenuates later life odor fear conditioning and amygdala activity. In the present work we investigated whether changes observed in adults can also be observed in other structures normally involved, namely olfactory cortical areas. For this, pups were trained daily from postnatal (PN) 8 to 12 in an odor-shock paradigm, and retrained at adulthood in the same task. 14C 2-DG autoradiographic brain mapping was used to measure training-related activation in amygdala cortical nucleus (CoA), anterior (aPCx), and posterior (pPCx) piriform cortex. In addition, field potentials induced in the three sites in response to paired-pulse stimulation of the olfactory bulb were recorded in order to assess short-term inhibition and facilitation in these structures. Attenuated adult fear learning was accompanied by a deficit in 2-DG activation in CoA and pPCx. Moreover, electrophysiological recordings revealed that, in these sites, the level of inhibition was lower than in control animals. These data indicate that early life odor-shock learning produces changes throughout structures of the adult learning circuit that are independent, at least in part, from those involved in infant learning. Moreover, these enduring effects were influenced by the contingency of the infant experience since paired odor-shock produced greater disruption of adult learning and its supporting neural pathway than unpaired presentations. These results suggest that some enduring effects of early life experience are potentiated by contingency and extend beyond brain areas involved in infant learning.
Comparative Analyses of Arabidopsis complex glycan1 Mutants and Genetic Interaction with staurosporin and temperature sensitive3a
Authors: Frank Julia , Kaulfürst-Soboll Heidi , Rips Stephan , Koiwa Hisashi , von Schaewen Antje
Published: September 2008

We compare three Arabidopsis (Arabidopsis thaliana) complex glycan1 (cgl1) alleles and report on genetic interaction with staurosporin  and temperature sensitive3a (stt3a). STT3a encodes a subunit of oligosaccharyltransferase that affects efficiency of N-glycan transfer to nascent secretory proteins in the endoplasmic reticulum; cgl1 mutants lack N-acetyl-glucosaminyltransferase I activity and are unable to form complex N-glycans in the Golgi apparatus. By studying CGL1-green fluorescent protein fusions in transient assays, we show that the extra N-glycosylation site created by a point mutation in cgl1 C5 is used in planta and interferes with folding of full-length membrane-anchored polypeptides in the endoplasmic reticulum. Tunicamycin treatment or expression in the stt3a-2 mutant relieved the folding block, and migration to Golgi stacks resumed. Complementation tests with C5-green fluorescent protein and other N-glycosylation variants of CGL1 demonstrated that suppression of aberrant N-glycosylation restores activity. Interestingly, CGL1 seems to be functional also as nonglycosylated enzyme. Two other cgl1 alleles showed splicing defects of their transcripts. In cgl1 C6, a point mutation affects the 3′ splice site of intron 14, resulting in frame shifts; in cgl1-T, intron 11 fails to splice due to insertion of a T-DNA copy. Introgression of stt3a-2 did not restore complex glycan formation in cgl1 C6 or cgl1-T but suppressed the N-acetyl-glucosaminyltransferase I defect in cgl1 C5. Root growth assays revealed synergistic effects in double mutants cgl1 C6 stt3a-2 and cgl1-T  stt3a-2 only. Besides demonstrating the conditional nature of cgl1 C5 in planta, our observations with loss-of-function alleles cgl1 C6 and cgl1-T in the stt3a-2 underglycosylation background prove that correct N-glycosylation is important for normal root growth and morphology in Arabidopsis.
Quantitative estimation of incompatibility stresses and elastic energy stored in ferritic steel
Authors: Baczmanski A. , Lipinski P. , Tidu A. , Wierzbanowski K. , Pathiraj B.
Published: September 2008

Plastic incompatibility second-order stresses were determined for different orientations of a polycrystalline grain, using X-ray diffraction data and results of the self-consistent elasto-plastic model. The stresses in cold rolled ferritic steel were determined both in as-received and under tensile loaded conditions. It has been shown that the Reuss model and the self-consistent model applied to near surface volume provide the best approaches to determine diffraction elastic constants. For the first time, the elastic energy in an anisotropic material (arising from plastic incompatibilities between grains having various lattice orientations) has been determined. The second-order incompatibility stresses and stored elastic energy are presented in Euler space.
Characteristics and modifying factors of asbestos‐induced oxidative DNA damage
Authors: Jiang Li , Nagai Hirotaka , Ohara Hiroki , Hara Shigeo , Tachibana Mitsuhiro , Hirano Seishiro , Shinohara Yasushi , Kohyama Norihiko , Akatsuka Shinya , Toyokuni Shinya
Published: September 2008

Respiratory exposure to asbestos has been linked with mesothelioma in humans. However, its carcinogenic mechanism is still unclear. Here we studied the ability of chrysotile, crocidolite and amosite fibers to induce oxidative DNA damage and the modifying factors using four distinct approaches. Electron spin resonance analyses revealed that crocidolite and amosite containing high amounts of iron, but not chrysotile, catalyzed hydroxyl radical generation in the presence of H2O2, which was enhanced by an iron chelator, nitrilotriacetic acid, and suppressed by desferal. Natural iron chelators, such as citrate, adenosine 5′‐triphosphate and guanosine 5′‐triphosphate, did not inhibit this reaction. Second, we used time‐lapse video microscopy to evaluate how cells cope with asbestos fibers. RAW264.7 cells, MeT‐5 A and HeLa cells engulfed asbestos fibers, which reached not only cytoplasm but also the nucleus. Third, we utilized supercoiled plasmid DNA to evaluate the ability of each asbestos to induce DNA double strand breaks (DSB). Crocidolite and amosite, but not chrysotile, induced DNA DSB in the presence of iron chelators. We cloned the fragments to identify break sites. DSB occurred preferentially within repeat sequences and between two G:C sequences. Finally, i.p. administration of each asbestos to rats induced not only formation of nuclear 8‐hydroxy‐2′‐deoxyguanosine in the mesothelia, spleen, liver and kidney but also significant iron deposits in the spleen. Together with the established carcinogenicity of i.p. chrysotile, our data suggest that asbestos‐associated catalytic iron, whether constitutional or induced by other mechanisms, plays an important role in asbestos‐induced carcinogenesis and that chemoprevention may be possible through targeting the catalytic iron. (Cancer Sci 2008; 99: 2142–2151)
Duplicate breath testing to confirm eradication of Helicobacter pylori: incremental benefit and cost in 419 patients
Authors: VAKIL N. , ZULLO A. , RICCI C. , HASSAN C. , VAIRA D.
Published: September 2008

Background  Current standards for establishing a cure of H. pylori infection require two breath tests taken at least 4 weeks apart, to be negative.

Aim  To determine the incremental cost and accuracy of repeating a urea breath test (UBT) in clinical practice.

Methods  We identified 419 patients with documented Helicobacter pylori infection who received eradication therapy and then had two breath tests, one 4 weeks and the second at least 8 weeks after the completion of treatment. H. pylori infection was documented at baseline by a positive rapid urease test and histology.

Results  In patients with successful eradication of H. pylori infection (n = 317), the mean ± standard deviation delta over baseline (DOB) value before treatment was 43 ± 29 ppm. Following treatment, the mean DOB in cured was 0.56 ± 2.1 ppm at 1 month and was similar to the value obtained at the second breath (0.68 ± 1; P = 0.39), which was performed 60 ± 71 days after the first UBT. In patients remaining infected (n = 102), the mean DOB at baseline was 47 ± 20 ppm. Four weeks after treatment, the DOB was 40 ± 32 ppm. The second UBT was performed 94 ± 72 days after the first and the DOB was significantly greater than the first (47 ± 28; P = 0.040). There was no discordant result between the first breath test and second breath test. At a cost of 30 euros/breath test, the incremental cost of a second breath test was 12 570 euros in this cohort with no incremental clinical benefit.

Conclusions  A single UBT, 4 weeks after treatment is as effective as two serial breath tests in confirming H. pylori eradication. The incremental cost of the second breath test is very high with no incremental clinical benefit.
Aberrant expression of BAFF receptor, a member of the tumor necrosis factor receptor family, in malignant cells of nonhematopoietic origins
Authors: Kohno Tomoko , Daa Tsutomu , Otani Hiroshi , Shimokawa Isao , Yokoyama Shigeo , Matsuyama Toshifumi
Published: September 2008

The acquired capability of evading apoptosis is one of the prerequisites for cancer development, and NF‐κB plays a critical role by inducing anti‐apoptotic molecules. In this study, we firstly carried out an expression‐cloning approach to isolate the responsible molecules in the NF‐κB activation pathway with the defective mutant cell line, COS‐A717. This cell line shows reduced constitutive basal activity of NF‐κB as compared with the parental COS cells. We successfully isolated genes with compensating activity for the pathway, and one gene encoded B‐cell activating factor receptor (BAFF‐R). However, a Northern blot analysis revealed that the BAFF‐R expression is not only limited to cells of B cell origin, but also is found in those with nonhematopoietic origins. In the human fibrosarcoma cell line HT1080, an immunohistochemical analysis revealed that the expression of BAFF‐R is not on the cell surface, but in the cytoplasm. The expression of BAFF was also detected, and the reduction of endogenous BAFF or BAFF‐R by siRNA decreased the basal NF‐κB activity. Lastly, from clinicopathological specimens, the associated expression of BAFF‐R and BAFF was demonstrated in osteosarcoma. We propose that an aberrant BAFF/BAFF‐R‐dependent autocrine mechanism may play a role in the development of certain types of cancer cells.
A proteomic screen reveals the mitochondrial outer membrane protein Mdm34p as an essential target of the F‐box protein Mdm30p
Authors: Ota Kazuhisa , Kito Keiji , Okada Satoshi , Ito Takashi
Published: September 2008

Ubiquitination plays various critical roles in eukaryotic cellular regulation and is medated by a cascade of enzymes including ubiquitin protein ligase (E3). The Skp1–Cullin–F‐box protein complex comprises the largest E3 family, in each member of which a unique F‐box protein binds its targets to define substrate specificity. Although genome sequencing uncovers a growing number of F‐box proteins, most of them have remained as “orphans” because of the difficulties in identification of their substrates. To address this issue, we tested a quantitative proteomic approach by combining the stable isotope labeling by amino acids in cell culture (SILAC), parallel affinity purification (PAP) that we had developed for efficient enrichment of ubiquitinated proteins, and mass spectrometry (MS). We applied this SILAC‐PAP‐MS approach to compare ubiquitinated proteins between yeast cells with and without over‐expressed Mdm30p, an F‐box protein implicated in mitochondrial morphology. Consequently, we identified the mitochondrial outer membrane protein Mdm34p as a target of Mdm30p. Furthermore, we found that mitochondrial defects induced by deletion of MDM30 are not only recapitulated by a mutant Mdm34p defective in interaction with Mdm30p but alleviated by ubiquitination‐mimicking forms of Mdm34p. These results indicate that Mdm34p is a physiologically important target of Mdm30p.
Altered bone marrow dendritic cell cytokine production to toll‐like receptor and CD40 ligation during chronic feline immunodeficiency virus infection
Authors: Lehman Tracy L. , O’Halloran Kevin P. , Fallon Samantha A. , Habermann Lindsey M. , Campbell Jennifer A. , Nordone Shila , Dean Gregg A. , Hoover Edward A. , Avery Paul R.
Published: September 2008

Impaired dendritic cell (DC) function is thought to be central to human immunodeficiency virus‐associated immunodeficiency. In this study, we examined the effect of chronic feline immunodeficiency virus (FIV) infection on DC cytokine production in response to microbial and T‐cell stimulation. Cytokine production after either Toll‐like receptor (TLR) or CD40 ligation in bone marrow‐derived DCs (BM‐DCs) was measured in naïve and chronically FIV‐infected cats. The BM‐DCs were stimulated with ligands to TLR‐2, ‐3, ‐4, ‐7 and ‐9 or cocultured with 3T3 cells expressing feline CD40 ligand. Ligation of TLR‐4 and TLR‐9 in BM‐DCs from infected cats resulted in a significant decrease in the ratio of interleukin‐12 (IL‐12) to IL‐10. Conversely, TLR‐7 ligation produced a significant increase in the IL‐12 : IL‐10 ratio in BM‐DCs from infected cats. No difference was noted for TLR‐3 ligation. RNA expression levels of TLR‐2, ‐3, ‐4, ‐7 and ‐9 were not significantly altered by FIV infection. CD40 ligation significantly elevated both IL‐10 and IL‐12 messenger RNA production but did not alter the IL‐12 : IL‐10 ratio. Chronic FIV infection alters the ratio of immunoregulatory cytokines produced by BM‐DCs in response to certain pathogen‐derived signals, which is probably relevant to the increased risk of opportunistic infections seen in lentiviral infection.
A role of fukutin, a gene responsible for Fukuyama type congenital muscular dystrophy, in cancer cells: a possible role to suppress cell proliferation
Authors: Yamamoto Tomoko , Kato Yoichiro , Shibata Noriyuki , Sawada Tatsuo , Osawa Makiko , Kobayashi Makio
Published: September 2008

Fukutin, a gene responsible for Fukuyama type congenital muscular dystrophy (FCMD), is presumably related to the glycosylation of α‐dystroglycan (α‐DG), involved in basement membrane formation. Hypoglycosylation of α‐DG plays a key role for the pathogenesis of FCMD. On the other hand, fukutin and α‐DG are also expressed in various non‐neuromuscular tissues. Recently, a role of α‐DG as a cancer suppressor has been proposed, because of a decrease of glycosylated α‐DG in cancers. In this study, function of fukutin was investigated in two cancer cell lines, focusing on whether fukutin is involved in the glycosylation of α‐DG in cancer cells and has any possible roles related to a cancer suppressor. Localization of fukutin and a result of laminin‐binding assay after RNA interference suggest that fukutin may be involved in the glycosylation of α‐DG in a small portion in these cancer cell lines. In Western blotting and immuno‐electron microscopy, localization of fukutin in the nucleus was suggested in addition to the Golgi apparatus and/or endoplasmic reticulum. Immunohistochemically, there were more Ki‐67‐positive cells and more nuclear staining of phosphorylated c‐jun after knockdown of fukutin in two cell lines. Fukutin appears to suppress cell proliferation through a system involving c‐jun, although it is unclear this process is related to α‐DG or not at present. The result may propose a possibility of another function of fukutin in addition to the glycosylation of α‐DG in cancer cells.
Temporal evolution of epithelial, vascular and interstitial lung injury in an experimental model of idiopathic pulmonary fibrosis induced by butyl‐hydroxytoluene
Authors: Parra Edwin Roger , Boufelli Gabriela , Bertanha Fernanda , Samorano Luciana de Paula , Aguiar Junior Armando Costa , Costa Fernanda Magalhães Arantes , Capelozzi Vera Luiza , Barbas‐Filho João Valente
Published: September 2008

This study was undertaken to test whether the structural remodelling of pulmonary parenchyma can be sequentially altered in a model and method that demonstrate the progression of the disease and result in remodelling within the lungs that is typical of idiopathic pulmonary fibrosis. Three groups of mice were studied: (i) animals that received 3‐5‐di‐tert‐butyl‐4‐hydroxytoluene (BHT) and were killed after 2 weeks (early BHT = 9); (ii) animals that received BHT and were killed after 4 weeks (late BHT = 11); (iii) animals that received corn oil solution (control = 10). The mice were placed in a ventilated Plexiglas chamber with a mixture of pure humidified oxygen and compressed air. Lung histological sections underwent haematoxylin–eosin, immunohistochemistry (epithelial, endothelial and immune cells) and specific staining (collagen/elastic fibres) methods for morphometric analysis. When compared with the control group, early BHT and late BHT groups showed significant decrease of type II pneumocytes, lower vascular density in both and higher endothelial activity. CD4 was increased in late BHT compared with early and control groups, while CD8, macrophage and neutrophil cells were more prominent only in early BHT. The collagenous fibre density were significantly higher only in late BHT, whereas elastic fibre content in late BHT was lower than that in control group. We conclude that the BHT experimental model is pathologically very similar to human usual interstitial pneumonia. This feature is important in the identification of animal models of idiopathic pulmonary fibrosis that can accurately reflect the pathogenesis and progression of the human disease.