bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting the effects of exploitation on male‐first sex‐changing fish
Authors: Molloy P. P. , Goodwin N. B. , Côté I. M. , Gage M. J. G. , Reynolds J. D.
Published: January 2007

Sex change is widespread among tropical marine fishes, many of which are targeted by fisheries. Conservation concerns have been raised that sex‐changing species may be particularly prone to overexploitation by size‐selective fishing. In the case of male‐first sex‐changers, populations may become egg limited if large females are disproportionately killed. However, if males reduce the size at which they change sex in response to higher female mortality, the population may still be sufficiently productive. We develop an age‐based model to explore the effects of fishing on two types of male‐first sex‐changing fish: one with flexibility in size‐at‐sex‐change and one without. These effects were compared with those of non‐sex‐changing populations with similar life‐history and population characteristics. The model predicts that if male‐first sex‐changers cannot respond to elevated female mortality by adjusting their size‐at‐sex‐change, the population will be more prone to recruitment limitation and extinction than non‐sex‐changers. These effects will be amplified as smaller individuals become susceptible to fishing mortality. However, if size‐at‐sex‐change is flexible, sex‐changers may be as resilient to fishing as non‐sex‐changers. Knowledge of a species' size‐at‐sex‐change, and the mechanisms controlling it, should be fundamental to the selection of fisheries conservation strategies.
Monitoring and conservation of critically reduced marine turtle nesting populations: lessons from the Cayman Islands
Authors: Bell C. D. , Solomon J. L. , Blumenthal J. M. , Austin T. J. , Ebanks‐Petrie G. , Broderick A. C. , Godley B. J.
Published: January 2007

Historically, nesting marine turtles were abundant in the Cayman Islands and were an integral part of the economy and culture. Today, nesting of loggerhead turtle Caretta caretta and green turtles Chelonia mydas takes place at very low levels. Hawksbill Eretmochelys imbricata nesting has not been recorded since 1999. We overview highly detailed monitoring data gathered over a 6‐year period allowing insight into the magnitude and spatial and temporal patterns of marine turtle nesting, cost‐effectiveness of monitoring such reduced populations, impacts of development on reproductive success and current threats to the recovery of the population. Nesting is diffuse and widely distributed for both nesting species on Grand and Little Cayman. Modelled nesting detection profiles for Grand Cayman show that in order to maintain data resolution, most sandy coastline must be surveyed throughout each season. However, in Little Cayman it may be possible to reduce effort. Legal take of adults and illegal take of eggs may be significantly impacting the remaining population. Surprisingly, we observed no significant correlation between density of coastal development and clutch density, adult emergence success or hatching success for either species. A significant relationship exists however, between density of coastal development and incidence of misorientation events in loggerhead hatchlings but not in green turtle hatchlings. Effective protection of known nesting habitat and the elimination of exploitation of remaining adults and eggs within the population are critical to its recovery.
Reassembling island ecosystems: the case of Lord Howe Island
Authors: Hutton I. , Parkes J. P. , Sinclair A. R. E.
Published: January 2007

Exotic species that invade remote islands, usually following human settlement, have had catastrophic effects on native biota. However, on islands it is increasingly feasible to eradicate key exotic species allowing extant native species to recover in situ or to return naturally. The practice of marooning threatened species on islands where the threat is absent, irrespective of whether the threatened species once occurred on the island, is well established. However, less focus has been given to the ‘island’ as the management unit on which to return extirpated species or related surrogates for extinct species. We use the example of Lord Howe Island as a case study to explore options for island restoration should the remaining critical exotic pests (rodents and perhaps owls in this case) be eradicated as planned. Lord Howe Island, in the south‐west Pacific Ocean, is remote, biologically diverse, has a high degree of endemism, and was only discovered by humans in 1778. Consequently, the original and exotic biota and their interactions are all better known than for many islands with a more ancient human history. Two species of plants, nine terrestrial birds, one bat and at least four invertebrates have been lost from the island since 1778. One plant and two invertebrates could be returned as conspecifics. One plant and all the terrestrial birds that are extinct could be replaced by closely related species from elsewhere in the Pacific Ocean. Decisions on replacing extinct species with surrogates should be based on the taxonomic relatedness of the candidates for reintroduction: the same species before subspecies before genera, with functional replacement being a further filter on candidates that are not the same species. In our opinion, taxa with functional equivalence but without taxonomic relatedness would not be acceptable candidates for reintroduction.
Priority areas of intraspecific diversity: Larzac, a global hotspot for facultative paedomorphosis in amphibians
Authors: Denoël M.
Published: January 2007

Although the designation of biodiversity hotspots is a valuable tool to improve conservation efforts, this is a concept primarily based on species diversity. In consequence, another component of biodiversity, adaptive variation, is often ignored in conservation and to my knowledge no attempt has been made to identify hotspots of remarkable intraspecific patterns. My aim was to focus on the process of facultative paedomorphosis (i.e. the retention of larval traits such as gills in adult variants), a rare developmental pathway. One hundred and seventy‐four ponds were inventoried in Larzac (France) to determine the distribution and abundance of paedomorphic palmate newts Triturus helveticus (Amphibia, Caudata) and to compare these results with the current distribution of paedomorphs in this and other species. During this study, paedomorphic newts were found in 46 ponds, 32 of which were described here for the first time. Seventy‐nine per cent of known paedomorphic populations of this species were found there, whereas this area covers only 0.5% of the distribution area of the species. This represents the highest known density of facultatively paedomorphic populations, all species being considered. Because these populations face a high threat of disappearance, Larzac should be designated as an intraspecific biodiversity hotspot in order to protect adaptive intraspecific variation. Future conservation‐oriented work should focus not only on species distributions but also on phenotypically diverse but spatially localized variation.
Patterns and perceptions of wildlife crop raiding in and around Kerinci Seblat National Park, Sumatra
Authors: Linkie M. , Dinata Y. , Nofrianto A. , Leader‐Williams N.
Published: January 2007

Crop raiding can reduce farmers' tolerance towards wildlife. Despite higher human population densities in rural areas, and more rapid conversion of forest to farmland, much less is known about crop raiding in Asia than in Africa. Over 14 months, we identified perceived and actual crop pests, and their patterns of crop raiding from farmland in and around Kerinci Seblat National Park, Sumatra. Farmers named either the wild boar Sus scrofa (80%) or the pig‐tailed macaque Macaca nemestrina (20%) as the two most destructive crop pests. From 5125 crop raids by 11 species of mammal, most raids were indeed made by the wild boar (56%) and the pig‐tailed macaque (19%). For all species combined, temporal crop raiding peaks were positively correlated with periods of high rainfall. Spatially, most crop raids occurred nearest to the forest edge and the local guarding strategies used were ineffective. However, raids by wild boars were more extensive than raids by pig‐tailed macaques, which caused much greater crop damage (73%) than wild boars (26%), contrary to farmers' perceptions. Our research suggests that alternative mitigation strategies need to be trialed over dry and rainy seasons to identify the most effective strategies and that guarding effort should be increased during the rainy seasons and tailored towards specific crop raiding species based on their unique spatial patterns.
Who ate all the pride? Patriotic sentiment and English national football support
Authors: ABELL JACKIE , CONDOR SUSAN , LOWE ROBERT D. , GIBSON STEPHEN , STEVENSON CLIFFORD
Published: January 2007

ABSTRACT. The growing popularity of English national insignia in international football tournaments has been widely interpreted as evidence of the emergence of a renewed English national consciousness. However, little empirical research has considered how people in England actually understand football support in relation to national identity. Interview data collected around the time of the Euro 2000 and the 2002 World Cup tournaments fail to substantiate the presumption that support for the England football team maps onto claims to patriotic sentiment in any straightforward way. People with far‐right political affiliations did generally use national football support to symbolise a general pride in English national identity. However, other people either claimed not to support the England national team precisely because of its associations with nationalism, or else bracketed the domain of football support from more general connotations of English patriotism.
Liberal nationalism and the nationalisation of liberal values*
Authors: LÆGAARD SUNE
Published: January 2007

ABSTRACT. This article considers whether appeals to ‘national values’ in public discourse and political debate might be a form of nationalism. This theoretical question about the applicability of the category of nationalism faces the objections that political values cannot constitute nationality, and that this is even more so the case when the values in question are liberal, as they often are. Against these objections, it is argued that ‘the nationalisation of liberal values’ may, and in some contexts of immigration and Europeanisation probably do, exhibit ‘boundary mechanisms’ that are among the central features of nationalism. This feature of the nationalisation of liberal values carries both normative and explanatory implications, which relate to the concerns of ‘liberal nationalism’.
Max Weber on ‘ethnic communities’: a critique
Authors: BANTON MICHAEL
Published: January 2007

ABSTRACT.An untitled draft found among Weber's posthumous papers was published. In English translation it was given the title `Ethnic Groups'. In theMax Weber Gesamtausgabeit is titled `Ethnic Communities'. In this manuscript, Weber treated the feeling of belonging together because of shared ethnic origin as a social construct, underlain by a desire to monopolise power and status. Subsequently, Weber determined to put an end to the use of collectivist concepts, but at the time of writing he treated groups as real entities, instead of using the concept of group as an aid in the explanation of behaviour. The causal connections in ethnic group formation and maintenance have been more closely identified in subsequent sociological analysis.
Nationalism and the Internet*
Authors: ERIKSEN THOMAS HYLLAND
Published: January 2007

ABSTRACT. The territorial integrity of nations is often taken as the premise for a functioning, unifying national identity. Yet, the economic and technological developments of recent decades have made it necessary to question this assumption. It can no longer be taken for granted that the people who identify with a given nation inhabit the same space, nor can it be assumed that cultural homogenisation takes place at the level of the nation through mass media. When the Internet appeared, many social scientists and commentators predicted that it would threaten the cultural integrity of nations; that the non‐territorial character of the Internet would lead to fragmentation and unprecedented cultural differentiation, making it difficult, eventually impossible, to uphold a collective sense of national identity based on shared images, representations, myths and so on. Although it is too early to draw any conclusions regarding the long‐term effects of the Internet, experiences so far suggest that such predictions were mistaken. In fact, nations thrive in cyberspace, and the Internet has in the space of only a few years become a key technology for keeping nations (and other abstract communities) together. Nations which have lost their territory (such as Afrikaner‐led South Africa), nations which are for political reasons dispersed (such as Tamil Sri Lanka or Kurdistan), nations with large temporary overseas diasporas (such as Scandinavian countries, with their large communities in Spain during winter), or nations where many citizens work abroad temporarily or permanently (such as India or Caribbean island‐states), appear in many sites on the Internet – from online newspapers and magazines to semi‐official information sites and ‘virtual community’ homepages. In a ‘global era’ of movement and deterritorialisation, the Internet is used to strengthen, rather than weaken, national identities.
Reconsidering otherness: constructing Estonian identity*
Authors: PETERSOO PILLE
Published: January 2007

ABSTRACT. The concept of the Other is increasingly popular in nationalism and ethnicity literature, which usually proposes the existence of one significant Other for any national Self, and that this Other is usually threatening and negative. This approach is one‐sided and in need of revision. I suggest that any nation may have many simultaneously existing Others, and more importantly, these Others need not be negative – they may also be positive. By exploring how (1) ‘the Other’ matters in identity construction; (2) there can be several Others at any one time; (3) the Other can be positive as well as negative; (4) the role of any given Other can change during various phases of national identity construction and maintenance; and (5) the particular ‘otherness’ of the Other has social and political consequences, this article will reconsider the role of otherness in the construction, transformation and maintenance of Estonian national identity.
From national inclusion to economic exclusion: ethnic Hungarian labour migration to Hungary*
Authors: FOX JON E.
Published: January 2007

ABSTRACT.Over the past fifteen years, Hungarian nationalists have been redefining membership in the Hungarian nation to include all Hungarians in the region, irrespective of citizenship. This deterritorialised notion of the nation has been given increased discursive and institutional legitimacy. But ethnic Hungarians from Romania who have gone to Hungary in search of work have not discovered national unity. Rather, the vision of national inclusion preferred by elites has been met by the reality of economic and national exclusion engendered through labour migration. The migrants' national self‐understandings have taken shape not in accordance with the wishes of nationalist elites, but rather in response to the economic imperatives of labour migration. Rather than deducing the salience of national unity from its political privileging, the purpose of this paper is to explain how national disunity is experienced, constituted and reproduced in the context of ethnic Hungarian labour migration.
Kurdish nationalists and non‐nationalist Kurdists: rethinking minority nationalism and the dissolution of the Ottoman Empire, 1908–1909
Authors: KLEIN JANET
Published: January 2007

ABSTRACT. Recent scholarship has begun to nuance the idea of Ottoman decline, but few works have attempted to see nationalism outside of the dominant decline paradigm. By addressing the emergence of Kurdish nationalism in the late Ottoman period, this paper questions the idea that imperial disintegration and nationalism were inherently intertwined; and challenges not only the mutually causal relationship that has been emphasised in literature to date, but also the shape that the ‘nationalist movement’ took. Using archival sources, the Kurdish‐Ottoman press, travel literature and secondary sources in various languages, the present paper will illustrate how the so‐called Kurdish nationalist movement' was actually several different movements, each with a differing vision of the political entity its participants hoped to create or protect through their activities. The idea of Kurdish nationalism, or Kurdism, may have been present in the minds of these activists, but the notion of what it meant was by no means uniform. Different groups imbued the concept with their own meanings and agendas. This study demonstrates that most ‘nationalists’ among the Kurds continued to envision themselves as members of the multi‐national Ottoman state, the temptingly powerful rise of nationalism in their day notwithstanding. The suggestion has important implications for students and scholars of nationalist movements among other non‐dominant groups, not only in the Ottoman Empire but in contemporaneous empires such as the Habsburg, and in later states like Iraq, Rwanda and Sudan. The present study further questions the received wisdom that multi‐ethnic entities are a recipe for disaster. It proposes that a joint effort to rethink what we know about minority nationalism may involve not only a reconceptualisation of the very terms we use, but perhaps an accompanying shift in approach too.
Alfred Marshall's economic nationalism
Authors: NAKANO TAKESHI
Published: January 2007

ABSTRACT. Alfred Marshall has been seen as an economic liberal and one of the founders of the neo‐classical school. However, this article challenges such conventional wisdom and argues that Marshall is best understood as an economic nationalist. Economic nationalism has been falsely associated with mercantilism, the zero‐sum view of international economies, and so on. However, a new approach for studying economic nationalism has recently been proposed to redefine its conception. The present article shows that Marshall's economic thought is compatible with this new conception of economic nationalism. Marshall emphasised the role of nationality in the economic process. The characteristics of his economic thought, such as the evolutionary view of economy, conform more closely to Friedrich List's economic nationalism than to economic liberalism. By portraying Marshall's theory as that of economic nationalism, the author concludes that economic nationalism can have a systematic theory.
Differential glutamate‐dependent and glutamate‐independent adenosine A1 receptor‐mediated modulation of dopamine release in different striatal compartments
Authors: Borycz Janusz , Pereira M. Fátima , Melani Alessia , Rodrigues Ricardo J. , Köfalvi Attila , Panlilio Leigh , Pedata Felicita , Goldberg Steven R. , Cunha Rodrigo A. , Ferré Sergi
Published: January 2007

Adenosine and dopamine are two important modulators of glutamatergic neurotransmission in the striatum. However, conflicting reports exist about the role of adenosine and adenosine receptors in the modulation of striatal dopamine release. It has been previously suggested that adenosine A1 receptors localized in glutamatergic nerve terminals indirectly modulate dopamine release, by their ability to modulate glutamate release. In the present study, using in vivo microdialysis, we provide evidence for the existence of a significant glutamate‐independent tonic modulation of dopamine release in most of the analyzed striatal compartments. In the dorsal, but not in the ventral, part of the shell of the nucleus accumbens (NAc), blockade of A1 receptors by local perfusion with the selective A1 receptor antagonist 8‐cyclopentyl‐1,3‐dimethyl‐xanthine or by systemic administration of the non‐selective adenosine antagonist caffeine induced a glutamate‐dependent release of dopamine. On the contrary, A1 receptor blockade induced a glutamate‐independent dopamine release in the core of the NAc and the nucleus caudate–putamen. Furthermore, using immunocytochemical and functional studies in rat striatal synaptosomes, we demonstrate that a fraction of striatal dopaminergic terminals contains adenosine A1 receptors, which directly inhibit dopamine release independently of glutamatergic transmission.
NAC1, a cocaine‐regulated POZ/BTB protein interacts with CoREST
Authors: Korutla Laxminarayana , Degnan Ryan , Wang Peijie , Mackler Scott A.
Published: January 2007

In this report, CoREST was identified as a protein that interacts with NAC1. NAC1 is a cocaine‐regulated Pox virus and Zinc finger/Bric‐a‐brac Tramtrack Broad complex (POZ/BTB) repressor protein, which mediates interactions among several other transcriptional regulators. In the present study, an interaction between NAC1 and CoREST was detected in neuro‐2A cells and HEK293T cells. We found that the POZ/BTB domain is necessary and sufficient for interaction with CoREST. Surprisingly, only one of five mutations in the POZ/BTB domain that disrupts homodimer assembly interfered with NAC1 and CoREST interactions. These results indicate that POZ/BTB homodimer formation is not required for NAC1–CoREST interaction. CoREST demonstrated protein–protein interactions with both isoforms of NAC1, sNAC1, and lNAC1. Coimmunoprecipitation studies show that NAC1 and CoREST are physically bound together. To further support the results, a direct interaction was demonstrated in glutathione‐S‐transferase pull down assays. siRNA directed against NAC1 mRNA significantly reduced NAC1 protein expression and resulted in reversal of CoREST‐mediated repression in cells. This interaction between NAC1 and CoREST was not found for other POZ/BTB proteins tested. Endogenous interaction was demonstrated in lysates from rat brain samples. This is the first report to demonstrate that a POZ/BTB protein interacts with CoREST. Taken together, the results indicate that CoREST may be part of the NAC1 repressor mechanism.
Extracellular cAMP inhibits D1 dopamine receptor expression in CAD catecholaminergic cells via A2a adenosine receptors
Authors: Do Thuy , Sun Qian , Beuve Annie , Kuzhikandathil Eldo V.
Published: January 2007

The expression of D1 dopamine (DA) receptor gene is regulated during development, aging, and pathophysiology. The extracellular factors and signaling mechanisms that modulate the expression of D1 DA receptor have not been well characterized. Here, we present novel evidence that endogenous D1 DA receptor expression is inhibited by extracellular cAMP in the Cath.A Derived (CAD) catecholaminergic neuronal cell line. CAD cells express the multi‐drug resistance protein 5 transporters and secrete cAMP. Addition of exogenous cAMP decreases D1 receptor mRNA and protein greater than fourfold in 24 h. The cAMP‐induced decrease of D1 receptor mRNA levels is blocked by cGMP and by 1,3‐dipropyl‐8‐(p‐sulfo‐phenyl)xanthine, an inhibitor of ecto‐phosphodiestrase. Extracellular AMP, a metabolite of cAMP, also independently decreased D1 receptor mRNA levels. Inhibitors of ecto‐nucleotidases, α,β‐methyleneadenosine 5′‐di‐phosphate and GMP, completely blocked the decrease of D1 receptor mRNA by extracellular cAMP, but only partially blocked the decrease induced by extracellular AMP. Levamisole, an inhibitor of tissue non‐specific alkaline phosphatase, completely blocked the AMP‐induced decrease of D1 receptor mRNA. The extracellular cAMP, AMP, and adenosine (ADO)‐induced decrease in D1 receptor mRNA expression are mediated by A2a ADO receptor subtype. The results suggest a novel molecular mechanism linking activation of A2a ADO receptors with inhibition of D1 DA receptor expression.
Cyclin D1, cdk4, and Bim are involved in thrombin‐induced apoptosis in cultured cortical neurons
Authors: Rao Haripriya Vittal , Thirumangalakudi Lakshmi , Desmond Paula , Grammas Paula
Published: January 2007

Thrombin, a multifunctional serine protease, is neurotoxic in vitro and in vivo. Thrombin has been shown to be increased in Alzheimer’s disease (AD) and other neuropathological conditions and could be a mediator of pathological neuronal cell death in the brain. The mechanisms of thrombin‐induced neuronal cell death are incompletely understood. The objective of this study is to explore mechanisms that contribute to thrombin‐induced neuronal apoptosis focusing on the role of cell cycle regulators and the pro‐apoptotic protein Bim (Bcl‐2‐interacting mediator of cell death) in this process. Our data show that thrombin treatment of primary cerebral cortical cultures results in dose‐dependent apoptotic cell death. Exposure of neuronal cultures to thrombin leads to induction of cell cycle proteins cyclin D1 and cyclin E, at both mRNA and protein levels. In addition, thrombin treatment causes the appearance of cyclin‐dependent kinase 4 (cdk4) and expression of the pro‐apoptotic protein Bim. Inhibition of cdk4 prevents both induction of Bim expression and thrombin‐induced neuronal apoptosis. These data demonstrate that thrombin‐induced apoptosis proceeds via cell cycle activation involving cdk4 resulting in induction of Bim. Thus, cell cycle proteins could be therapeutic targets in diseases such as AD where thrombin has been implicated.
The requirement of Ras and Rap1 for the activation of ERKs by cAMP, PACAP, and KCl in cerebellar granule cells
Authors: Obara Yutaro , Horgan Angela M. , Stork Philip J. S.
Published: January 2007

In cerebellar granule cells, the mitogen‐activated protein kinase (MAPK) or extracellular signal‐regulated kinase (ERK) cascade mediates multiple functions, including proliferation, differentiation, and survival. In these cells, ERKs are activated by diverse stimuli, including cyclic adenosine monophosphate (cAMP), pituitary adenylate cyclase activating protein (PACAP), depolarization induced by elevated extracellular potassium (KCl), and the neurotrophin brain‐derived neurotrophic factor. Extensive studies in neuronal cell lines have implicated the small G proteins Ras and Rap1 in the activation of ERKs by cAMP, PACAP, and KCl. However, the requirement of Ras and Rap1 in these pathways in cerebellar granule cells has not been addressed. In this study, we utilize multiple biochemical assays to determine the mechanisms of action and requirement of Ras and Rap1 in cultured cerebellar granule cells. We show that both Ras and Rap1 can be activated by cAMP or PACAP via protein kinase (PKA)‐dependent mechanisms. KCl activation of Ras also required PKA. Using both adenoviral and transgenic approaches, we show that Ras plays a major role in ERK activation by cAMP, PACAP, and KCl, while Rap1 also mediates activation of a selective membrane‐associated pool of ERKs. Furthermore, Rap1, but not Ras, activation by PKA appears to require the action of Src family kinases.
FAD mutants unable to increase neurotoxic Aβ 42 suggest that mutation effects on neurodegeneration may be independent of effects on Aβ
Authors: Shioi Junichi , Georgakopoulos Anastasios , Mehta Pankaj , Kouchi Zen , Litterst Claudia M. , Baki Lia , Robakis Nikolaos K.
Published: January 2007

Strong support for a primary causative role of the Aβ peptides in the development of Alzheimer’s disease (AD) neurodegeneration derives from reports that presenilin familial AD (FAD) mutants alter amyloid precursor protein processing, thus increasing production of neurotoxic Aβ 1–42 (Aβ 42). This effect of FAD mutants is also reflected in an increased ratio of peptides Aβ 42 over Aβ 1–40 (Aβ 40). In the present study, we show that several presenilin 1 FAD mutants failed to increase production of Aβ 42 or the Aβ 42/40 ratio. Our data suggest that the mechanism by which FAD mutations promote neurodegeneration and AD may be independent of their effects on Aβ production.
Serotonin transporter function, but not expression, is dependent on brain‐derived neurotrophic factor (BDNF): in vivo studies in BDNF‐deficient mice
Authors: Daws L. C. , Munn J. L. , Valdez M. F. , Frosto‐Burke T. , Hensler J. G.
Published: January 2007

In the present study, we used high‐speed chronoamperometry to examine serotonin (5‐HT) transporter (5‐HTT) function in vivo in 2‐, 5‐, and 10‐month‐old brain‐derived neurotrophic factor (BDNF)+/− mice. The rate of clearance of exogenously applied 5‐HT was measured in CA3 region of hippocampus. In 2‐month‐old mice, the rate of 5‐HT clearance did not differ between BDNF+/+ and BDNF+/− mice. In BDNF+/+ mice, 5‐HT clearance rate (Tc) increased markedly with age. In contrast, Tc remained relatively static in BDNF+/− mice across 2‐, 5‐, and 10‐month age groups. At 5 months of age, female BDNF+/+ mice had a lower maximal velocity (Vmax) for 5‐HT clearance than male BDNF+/+ mice. There was a similar trend in 5‐month‐old BDNF+/− mice, but this did not reach statistical significance. There was an age‐dependent increase in KT value for 5‐HT clearance (i.e., decreased in vivo affinity of 5‐HTT), but no significant effect of genotype or gender. 5‐HTT density, as measured by [3H]cyanoimipramine binding, was not different between BDNF+/+ and BDNF+/− mice, although there was a significant increase in 5‐HTT binding with age. The selective 5‐HT reuptake inhibitor fluvoxamine (50 and 100 pmol) significantly decreased 5‐HT clearance in BDNF+/+ mice, but not in BDNF+/− mice. Our data suggest that the profoundly reduced ability of 5‐ and 10‐month‐old BDNF+/− mice to clear 5‐HT is not because of a decrease in the total number of 5‐HTTs, but may be due to functional deficits in the 5‐HTT, e.g., in the machinery/signaling required for insertion of 5‐HTTs into the plasma membrane and/or activation of the 5‐HTT once it is positioned to take up 5‐HT from extracellular fluid.
Phospholipase C‐related inactive protein is implicated in the constitutive internalization of GABAAreceptors mediated by clathrin and AP2 adaptor complex
Authors: Kanematsu Takashi , Fujii Makoto , Mizokami Akiko , Kittler Josef T. , Nabekura Junichi , Moss Stephen J. , Hirata Masato
Published: January 2007

A mechanism for regulating the strength of synaptic inhibition is enabled by altering the number of GABAAreceptors available at the cell surface. Clathrin and adaptor protein 2 (AP2) complex‐mediated endocytosis is known to play a fundamental role in regulating cell surface GABAAreceptor numbers. Very recently, we have elucidated that phospholipase C‐related catalytically inactive protein (PRIP) molecules are involved in the phosphorylation‐dependent regulation of the internalization of GABAAreceptors through association with receptor β subunits and protein phosphatases. In this study, we examined the implications of PRIP molecules in clathrin‐mediated constitutive GABAAreceptor endocytosis, independent of phospho‐regulation. We performed a constitutive receptor internalization assay using human embryonic kidney 293 (HEK293) cells transiently expressed with GABAAreceptor α/β/γ subunits and PRIP. PRIP was internalized together with GABAAreceptors, and the process was inhibited by PRIP‐binding peptide which blocks PRIP binding to β subunits. The clathrin heavy chain, μ2 and β2 subunits of AP2 and PRIP‐1, were complexed with GABAAreceptor in brain extract as analyzed by co‐immunoprecipitation assay using anti‐PRIP‐1 and anti‐β2/3 GABAAreceptor antibody or by pull‐down assay using β subunits of GABAAreceptor. These results indicate that PRIP is primarily implicated in the constitutive internalization of GABAAreceptor that requires clathrin and AP2 protein complex.
Anxiety induced by prenatal stress is associated with suppression of hippocampal genes involved in synaptic function
Authors: Bogoch Y. , Biala Y. N. , Linial M. , Weinstock M.
Published: January 2007

Exposure of pregnant women or animals to stress during a critical period of foetal brain development increases the likelihood of anxiety, depression and learning deficits that are associated with structural alterations in the offspring hippocampus. In this study, we report the effect of gestational stress in rats on anxiogenic behaviour and hippocampal gene expression of their 23‐day‐old female offspring. As the rat brain continues to develop after birth, we also used the procedure of handling (H) during the first 10 days of life to reverse the anxiogenic behaviour of prenatally stressed (PS) rats. By means of micro‐array analysis on hippocampal extracts, we found that the expression of about 6.1% of 9505 valid genes was significantly altered by prenatal stress (p < 0.05). Of these, 48% were over‐expressed and 52% under‐expressed. The latter included ∼300 genes that participate in axonal growth, regulation of ion channels and transporters, trafficking of synaptic vesicles and neurotransmitter release. About 30% of the genes that were down‐regulated in PS rats were restored to control levels by H. These include genes that play a role in pre‐synaptic organization and function. Our results provide a possible relationship between hippocampal gene expression and changes in behaviour resulting from prenatal stress.
Visualization of 2‐arachidonoylglycerol accumulation and cannabinoid CB1 receptor activity in rat brain cryosections by functional autoradiography
Authors: Palomäki Ville A. B. , Lehtonen Marko , Savinainen Juha R. , Laitinen Jarmo T.
Published: January 2007

In neuronal signalling mediated by the endocannabinoid 2‐arachidonoylglycerol, both synthetic and inactivating enzymes operate within close proximity to the Gi/o‐coupled pre‐synaptic CB1 receptors, thus allowing for rapid onset and transient duration of this lipid modulator. In rat brain, 2‐arachidonoylglycerol is inactivated mainly via hydrolysis by serine hydrolase inhibitor‐sensitive monoacylglycerol lipase activity. We show in this study that comprehensive pharmacological elimination of this activity in brain cryosections by methyl arachidonylfluorophosphonate or hexadecylsulphonyl fluoride results in endocannabinoid‐mediated CB1 receptor activity, which can be visualized by functional autoradiography. URB597, a specific inhibitor of anandamide hydrolysis proved ineffective. TLC indicated that the bioactivity resided in 2‐arachidonoylglycerol‐containing fraction and gas chromatography–mass spectroscopy detected elevated levels of monoacylglycerols, including 2‐arachidonoylglycerol in this fraction. Although two diacylglycerol lipase inhibitors, tetrahydrolipstatin (THL) and RHC80267, blocked the bulk of 2‐arachidonoylglycerol accumulation in methyl arachidonylfluorophosphonate‐treated sections, only THL reversed the endocannabinoid‐dependent CB1 receptor activity. Further studies indicated that at the used concentrations, THL rather specifically antagonized the CB1 receptor. These findings confirm that in brain sections there is preservation of enzymatic pathways regulating the production of endogenous receptor ligands. Furthermore, the presently described methodology may serve as an elegant and intuitive approach to identify novel membrane‐derived lipid modulators operating in the CNS.
Recognition molecules and neural repair
Authors: Loers Gabriele , Schachner Melitta
Published: January 2007

Neural recognition molecules were discovered and characterized initially for their functional roles in cell adhesion as regulators of affinity between cells and the extracellular matrix in vitro. They were then recognized as mediators or co‐receptors which trigger signal transduction mechanisms affecting cell adhesion and de‐adhesion. Their involvement in contact attraction and repulsion relies on cell‐intrinsic properties that are modulated by the spatial contexts of their expression at particular stages of ontogenetic development, in synaptic plasticity and during regeneration after injury. The functional roles of recognition molecules in cell proliferation and migration, determination of developmental fate, growth cone guidance, and synapse formation, stabilization and modulation have been well documented not only by in vitro, but also by in vivo studies that have been greatly aided by generation of genetically altered mice. More recently, the functions of recognition molecules have been investigated under conditions of neural repair and manipulated using a broad range of genetic and pharmacological approaches to achieve a beneficial outcome. The principal aim of most therapeutically oriented approaches has been to neutralize inhibitory factors. However, less attention has been paid to enhancing repair by stimulating the stimulatory factors. When considering potential therapeutic strategies, it is worth considering that a single recognition molecule can possess domains that are conducive or repellent and that the spatial distribution of recognition molecules can determine the overall function: Recognition molecules may be repellent for neurite outgrowth when presented as barriers or steep‐concentration gradients and conducive when presented as uniform substrates. The focus of this review will be on the more recent attempts to study the conducive mechanisms with the expectation that they may be able to tip the balance from a regeneration inhospitable to a hospitable environment. It is likely that a combination of the two principles, as multifactorial as each principle may be in itself, will be of therapeutic value in humans.
Neuroprotective actions of a histidine analogue in models of ischemic stroke
Authors: Tang Sung‐Chun , Arumugam Thiruma V. , Cutler Roy G. , Jo Dong‐Gyu , Magnus Tim , Chan Sic L. , Mughal Mohamed R. , Telljohann Richard S. , Nassar Matthew , Ouyang Xin , Calderan Andrea , Ruzza Paolo , Guiotto Andrea , Mattson Mark P.
Published: January 2007

Histidine is a naturally occurring amino acid with antioxidant properties, which is present in low amounts in tissues throughout the body. We recently synthesized and characterized histidine analogues related to the natural dipeptide carnosine, which selectively scavenge the toxic lipid peroxidation product 4‐hydroxynonenal (HNE). We now report that the histidine analogue histidyl hydrazide is effective in reducing brain damage and improving functional outcome in a mouse model of focal ischemic stroke when administered intravenously at a dose of 20 mg/kg, either 30 min before or 60 min and 3 h after the onset of middle cerebral artery occlusion. The histidine analogue also protected cultured rat primary neurons against death induced by HNE, chemical hypoxia, glucose deprivation, and combined oxygen and glucose deprivation. The histidine analogue prevented neuronal apoptosis as indicated by decreased production of cleaved caspase‐3 protein. These findings suggest a therapeutic potential for HNE‐scavenging histidine analogues in the treatment of stroke and related neurodegenerative conditions.
Identification of IRAS/Nischarin as an I1‐imidazoline receptor in PC12 rat pheochromocytoma cells
Authors: Sun Zheng , Chang Chung‐Ho , Ernsberger Paul
Published: January 2007

The I1‐imidazoline receptor (I1R) is a proposed target for drug action relevant to blood pressure and glucose control. The imidazoline receptor antisera‐selected (IRAS) gene, also known as Nischarin, has several characteristics of an I1R. To test the contribution of IRAS to I1R binding capacity and cell‐signaling function, an antisense probe targeting the initiating codon of rat IRAS gene was evaluated in PC12 rat pheochromocytoma cells, a well‐established model for I1R action. The density of I1R was significantly reduced by antisense compared with control transfection (Bmax = 400 ± 16 vs. 691 ± 29 fmol/mg protein), without significantly affecting binding affinity (Kd = 0.30 ± 0.04 vs. 0.39 ± 0.05 nmol/L). Thus, IRAS expression is necessary for high‐affinity binding to I1R. Western blots with polyclonal anti‐IRAS showed reduced IRAS expression in the major 85‐kDa band relative to an actin reference, paralleling the reduction in binding site density. To determine whether reduced IRAS expression attenuated I1R cell signaling, PC12 cells transfected with antisense or sense oligo‐DNA were treated with moxonidine, an I1R agonist, then cell lysates were analyzed by western blot. Dose‐dependent activation of extracellular signal‐regulated kinase was attenuated without affecting the potency of the agonist. In contrast, extracellular signal‐regulated kinase activation by insulin was unchanged. The IRAS gene is likely to encode an I1R or a functional subunit.
β‐Amyloid increases somatostatin expression in cultured cortical neurons
Authors: Geci Catherine , How Jonathan , Alturaihi Haydar , Kumar Ujendra
Published: January 2007

In β‐amyloid (Aβ)‐induced neurotoxicity, activation of the NMDA receptor, increased Ca2+ and oxidative stress are intimately associated with neuronal cell death as normally seen in NMDA‐induced neurotoxicity. We have recently shown selective sparing of somatostatin (SST)‐positive neurons and increased SST expression in NMDA agonist‐induced neurotoxicity. Accordingly, the present study was undertaken to determine the effect of Aβ25–35‐induced neurotoxicity on the expression of SST in cultured cortical neurons. Cultured cortical cells were exposed to Aβ25–35 and processed to determine the cellular content and release of SST into medium by radioimmunoassay and SST mRNA by RT‐PCR. Aβ25–35 induces neuronal cell death in a concentration‐ and time‐dependent fashion, increases SST mRNA synthesis and induces an augmentation in the cellular content of SST. No significant changes were seen on SST release at any concentration of Aβ25–35 after 24 h of treatment. However, Aβ25–35 induces a significant increase of SST release into medium only after 12 h in comparison with other time points. Most significantly, SST‐positive neurons are selectively spared in the presence of a lower concentration of Aβ25–35, whereas, in the presence of higher concentrations of Aβ25–35 for extended time periods, SST‐positive neurons decrease gradually. Furthermore, Aβ25–35 induces apoptosis at lower concentrations (5 and 10 μmol/L) and necrosis at higher concentrations (20 and 40 μmol/L). Consistent with the increased accumulation of SST, these data suggest that Aβ25–35 impairs cell membrane permeability. Selective sparing of SST‐positive neurons at lower concentrations of Aβ25–35 at early time points directly correlates with the pathophysiology of Alzheimer’s disease.
The effect of host plant on larval survivorship of the Alaskan swallowtail butterfly (Papilio machaon aliaska)
Authors: Murphy Shannon M.
Published: January 2007

The Alaskan swallowtail butterfly, Papilio machaon aliaska (Lepidoptera: Papilionidae), uses three plant species as host plants. Cnidium cnidiifolium (Turcz.) Schischk. belongs to the family Apiaceae, the ancestral host‐plant family of the P. machaon group. Artemisia arctica Less. and Petasites frigidus (L.) Franch, in contrast, belong to the distantly related Asteraceae family and were colonized relatively recently by this group of butterflies. Previous work has shown that larval survival is highest on the novel host plants when natural enemies are present in the field. Here I examine whether P. m. aliaska fitness varied when individuals were reared on the three host plants in a common environment, free of environmental and ecological complications such as predation. I collected 12 P. m. aliaska females and measured their reproductive success when their progeny were reared on each of the three host plants. I assessed larval fitness on each of the hosts by recording the percentage pupation and percentage emergence as well as by measuring pupal mass. I found that larvae reared on the ancestral host plant, C. cnidiifolium, had higher fitness than did larvae reared on either of the novel host plants, A. arctica or P. frigidus. Larvae reared on C. cnidiifolium were more likely to pupate, achieved a greater pupal mass, and had higher emergence rates than larvae reared on the novel hosts. I interpret these results to mean that, in the absence of predation, the ancestral host plant is a better host for P. m. aliaska larvae than either novel host and I contend that this result does not appear to support the hypothesis that P. m. aliaska populations in central Alaska are divided into host races.
Geographic origin affects larval competitive ability in European populations of the blow fly, Lucilia sericata
Authors: Martínez‐Sánchez A. , Smith K. E. , Rojo S. , Marcos‐García M. A. , Wall R.
Published: January 2007

The blow fly, Lucilia sericata (Meigen) (Diptera: Calliphoridae), is found throughout Europe. In northern areas, in addition to breeding in carrion, it can also commonly act as primary facultative ectoparasite of sheep, resulting in animal suffering and production losses. However, in the south of Europe, L. sericata is not usually implicated in myiasis and is found almost entirely in carrion. The causes of this behavioural difference are unclear. To begin to address the possible reasons for this difference, the present study examined the effects of competition on the survival and development of L. sericata populations derived from southern Spain, England, and a hybrid derived from a cross between Spanish females and UK males. Larvae were reared at a range of different initial densities and the mortality, development rate, and size of the resultant adults were measured. Mortality increased significantly with density, but the Spanish population had a significantly higher mortality rate than the UK population at all densities. Similarly, adult size declined with increased larval density, but individuals from the Spanish population were consistently larger than those from the UK population at all densities. The mortality and size of the hybrids was consistently intermediate between the Spanish and UK populations. No consistent effects on development rate were observed. This study demonstrates that insects from northwestern and southern European population have qualitatively different life history traits and competitive abilities and may contribute towards explaining the different behaviour of populations of this species in different part of its distribution range.
Hoverfly oviposition response to aphids in broccoli fields
Authors: Ambrosino M. D. , Jepson P. C. , Luna J. M.
Published: January 2007

The oviposition response of predacious hoverflies (Diptera: Syrphidae) toBrevicoryne brassicaeL. andMyzus persicae(Sulzer) (Homoptera: Aphididae) in commercial broccoli,Brassica oleraceavar.italicaL., Plenck (Brassicaceae), fields was investigated at two sites over the course of a growing season. The hoverfly oviposition responses to these aphid species on different parts of the broccoli plant canopy were also examined. There were no hoverfly eggs on broccoli plants without aphids, egg numbers were very low on plants with fewer than 50 aphids, and no peak in oviposition relative to aphid numbers was observed. Within individual plants that were colonized by aphids, there was some oviposition on individual leaves without aphids, and no hoverfly eggs were seen on leaves that had more than 400 aphids. Leaves in the broccoli plant canopy, and the datasets associated with them, were divided into three sections vertically, ‘upper’, ‘middle’, and ‘lower’.Brevicoryne brassicaewas more abundant in the upper and middle canopy sections, whileM. persicaewas found mostly in the lower section. The rate of hoverfly oviposition per aphid was higher in the upper section than in the two other sections. Modeling of the oviposition response using logistic regression showed that the presence of hoverfly eggs was positively correlated with numbers of each aphid species and sampling date.