bluuebunny/crossref_metadata_2025 huggingface dataset:
Transmission of Onchocerca volvulus and prospects for the elimination of its vector, the blackfly Simulium neavei in the Mpamba–Nkusi focus in Western Uganda
Authors: Lakwo T. L. , Ndyomugyenyi R. , Onapa A. W. , Twebaze C.
Published: March 2006

Abstract.  The transmission of Onchocerca volvulus Leuckart (Spirudida: Onchocercidae) and the prospects of Simulium neavei Roubaud (Diptera: Simuliidae) vector elimination through ground larviciding were investigated in the Mpamba–Nkusi focus, western Uganda. Transmission levels and the initiated vector elimination activities were assessed to supplement the ongoing ivermectin mass distribution programme. Searches for breeding sites, adult fly catches, dissection of flies, river treatment with temephos (Abate®) and a review of annual ivermectin treatment data were conducted. High levels of crab infestation with S. neavei sensu stricto immature stages were recorded; 57.9% and 100% for the Mpamba and Nyabugando river systems, respectively. The mean numbers of larvae/pupae per crab were 3.6 ± 0.5 in the Mpamba and 20.6 ± 1.8 in the Nyabugando systems. Pre‐intervention mean biting densities were 39 and 32 flies/(man day) in 2001 and 2002, respectively, and an annual biting rate in 2001 of > 14 000. The bimodal biting pattern of S. neavei s.s. consisted of two peaks; one in the morning (09.00–10.00 hours) and one in the afternoon (14.00–15.00 hours) with a mid‐day lull in biting. The infection/infective rates were 13.3%/2.8% and 16.6%/2.9% in the dissected parous flies from the Mpamba and Nyabugando river systems, respectively. Out of ∼1000 parous flies, 129 and 109 were found to be harbouring infective larvae of Onchocerca volvulus in their heads from the Mpamba and Nyabugando river systems, respectively. In spite of the > 10 years of ivermectin treatment, at a mean coverage of 71.3%, infection remained relatively high. Ground larviciding with temephos (Abate®) initiated in June and October 2002 had a significant impact. In the Mpamba river system there was a significant (P < 0.001) reduction in positive crabs from 57.9% in 2001 to 0.06% in 2003 and a decrease in the mean number of larvae/pupae per crab from 3.6 ± 0.5 in 2001 to 0.0007 ± 0.0001 (P < 0.002) in 2003. Similarly, in the Nyabugando river system, a significant (P < 0.001) reduction in crab infestation from 100% in 2001 to 0.06% in 2003 and a decrease in the mean number of larvae/pupae per crab from 20.6 ± 1.8 in 2001 to 0.06 ± 0.03 in 2003. Drastic reductions were observed in the mean number of biting flies from 3 flies/h in 2001 to 0 flies/h in 2003 and the annual biting rates fell from 14 235 flies/year in 2001 to only 730 flies/year in 2003. These data suggest that substantial progress towards the goal of S. neavei s.s. vector elimination has been made and this will enhance the ongoing ivermectin treatment in this isolated focus.
First record and establishment of the mosquito Aedes albopictus in Spain
Authors: Aranda C. , Eritja R. , Roiz D.
Published: March 2006

Abstract.  The invasive mosquito Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) was detected for the first time in Spain, in Sant Cugat del Vallès, a city in the north‐east of the country (41°28′ N, 2°4′ E, altitude 120 m), during August 2004. A male and one larva were collected in the backyard of a house and in a tree hole, respectively. Dense populations of adults and larvae were found in subsequent surveys, confirming the establishment of the species in the area. This is the first report of the establishment of this species in the Iberian Peninsula.
Revision of the Ketaketa subcomplex of blackflies of the Simulium damnosum complex
Authors: Krueger A. , Mustapha M. , Kalinga A. K. , Tambala P. A. J. , Post R. J. , Maegga B. T. A.
Published: March 2006

Abstract.  A revision of the taxonomy of the Ketaketa subcomplex of the Simulium damnosum Theobald complex (Diptera: Simuliidae) is presented including new material from Tanzania, Malawi and South Africa. The cytotaxonomy, morphology and molecular identity of known and new taxa are described. The Ketaketa subcomplex is cytotaxonomically defined by the paracentric inversion 1L‐7. We recognize three sibling species, namely Simulium latipollex (Enderlein), Simulium plumbeum Krueger, sp.n. and Simulium kipengere Krueger, sp.n., the latter comprising three cytoforms: ‘Typical’, ‘Linthipe’ and ‘Mombo’. The cytoforms ‘Mwamphanzi’, ‘Ketaketa’ and ‘Hammerkopi’ are synonymized with S. plumbeum. Identification keys are provided on the basis of chromosomal and morphological characters. In view of their potential role as vectors of human onchocerciasis (river blindness) we also discuss the possible medical importance of the different cytoforms and their geographical distribution.
Microgeographical breeding structure of the tsetse fly, Glossina pallidipes in south‐western Kenya
Authors: Ouma J. O. , Marquez J. G. , Krafsur E. S.
Published: March 2006

Abstract.  The origins of extant Glossina pallidipes Austen (Diptera: Glossinidae) populations in the ecologically well‐studied Lambwe and Nguruman valleys in Kenya are controversial because populations have recovered after seemingly effective attempts to achieve high levels of control. The microgeographical breeding structure of the tsetse fly, G. pallidipes, was investigated by analysing spatial and temporal variation at eight microsatellite loci to test hypotheses about endemism and immigration. Samples were obtained at seasonal intervals from trap sites separated by 200 m to 14 km and arranged into blocks. G. pallidipes populations nearest to Lambwe and Nguruman also were sampled. Spatial analysis indicated that genetic differentiation by genetic drift was much less among trapping sites within Lambwe and Nguruman (FST ≤ 0.049) than between them (FST = 0.232). FST between Serengeti and Nguruman was 0.16 and FST between Kodera Forest and Lambwe was 0.15. The genetic variance in G. pallidipes explained by dry and wet seasons (0.33%) was about one‐fifth the variance among collection dates (1.6%), thereby indicating reasonable temporal stability of genetic variation. Gene frequencies in Kodera and Serengeti differed greatly from Lambwe and Nguruman, thereby falsifying the hypothesis that Lambwe and Nguruman were repopulated by immigrants. Harmonic mean effective (= breeding) population sizes were 180 in Lambwe and 551 in Nguruman. The genetic data suggest that G. pallidipes in Lambwe and Nguruman have been endemic for long intervals.
Orientation of Culex mosquitoes to carbon dioxide‐baited traps: flight manoeuvres and trapping efficiency
Authors: Cooperband M. F. , Cardé R. T.
Published: March 2006

Abstract.  Females of Culex quinquefasciatus Say and Culex tarsalis Coquillet (Diptera: Culicidae) in the host‐seeking stage were released and video recorded in three dimensions in a large field wind tunnel as they flew to four kinds of CO2‐baited mosquito traps. The trapping efficiency (number of mosquitoes approaching compared to the number caught) was determined for each trap type. The Encephalitis Virus Surveillance (EVS), Mosquito Magnet Freedom (MMF) and Mosquito Magnet Liberty (MML) traps captured only 13–16% of approaching Cx. quinquefasciatus females, whereas the Mosquito Magnet‐X (MMX) trap captured 58%. Similar results were obtained for Cx. tarsalis. Orientation behaviour and flight parameters of mosquitoes approaching the four traps were compared. Mosquitoes spent the most time orienting to the EVS trap. Flight speed decreased as mosquitoes entered the vicinity of each trap and a large portion of their time was spent within 30 cm downwind of the traps. Flights became highly tortuous downwind of the poorly performing traps and just upwind of the MMX trap. Differences between traps and possible explanations for the superior performance of the MMX trap are considered.
The Western Mediterranean lamproitic magmatism: origin and geodynamic significance
Authors: Peccerillo Angelo , Martinotti Giorgio
Published: March 2006

Ultrapotassic lamproitic rocks in the Western Alps, Tuscany‐Corsica and SE Spain (c. 30 to 1 Ma) show high MgO, Ni and Cr denoting a mantle origin, but also have incompatible element and radiogenic isotope abundances that resemble upper crustal rocks, such as local metapelites and global subducting sediments. The coexistence of mantle and crustal signatures in lamproites indicates a genesis in a lithospheric mantle, which had been contaminated by crustal rocks. The occurrence of lamproitic magmatism along the Alpine collision front suggests that mantle contamination occurred during east‐verging Cretaceous‐Oligocene subduction of the European plate beneath the African margin. We suggest that crustal material originated from the overriding continental margin, which was eroded by the low‐angle subducting European slab. Mantle melting and generation of lamproites took place later, during diachronous opening of Western Mediterranean basins, contemporaneously with a new cycle of magmatism, which was genetically related to the west‐north‐dipping Apennine‐Maghrebian subduction.
Transgressive segregation reveals two Arabidopsis TIR‐NB‐LRR resistance genes effective against Leptosphaeria maculans, causal agent of blackleg disease
Authors: Staal Jens , Kaliff Maria , Bohman Svante , Dixelius Christina
Published: March 2006

In a cross between the two resistant accessions Col‐0 and Ler‐0, a 15:1 segregation was found in F2, suggesting the presence of unlinked resistance loci to Leptosphaeria maculans. One hundred Col‐4 × Ler‐0, and 50 Ler‐2 × Cvi‐1 recombinant inbred lines, and seven susceptible Ler‐0 × Ws‐0 F2 progenies were examined to identify the two loci. Resistance in Col‐4, Ws‐0 and Cvi‐1 (RLM1) was mapped to the marker m305 on chromosome 1. Col‐4 × Ler‐0 and Ler‐2 × Cvi‐1 mapping populations located RLM2Ler on the same arm of chromosome 4. A tight physical location of RLM2 was established through near‐isogenic lines. This region was found to correspond to an ancient duplication event between the RLM1 and RLM2 loci. Two independent T‐DNA mutants in a TIR‐NB‐LRR R gene (At1g64070) displayed susceptibility, and L. maculans susceptible mutant phenotypes were confirmed to be allelic for rlm1 in F1 after crosses with susceptible rlm1Lerrlm2Col plants. Complementation of rlm1Lerrlm2Col with the genomic Col‐0 sequence of At1g64070 conferred resistance. In addition, two T‐DNA mutants in a neighbouring homologous TIR‐NB‐LRR gene (At1g63880) displayed moderate susceptibility to L. maculans. Sequence analysis revealed that At1g64070 was truncated by a premature stop codon, and that At1g63880 was absent in Ler‐0. RNA interference confirmed that Ler‐0 resistance is dependent on genes structurally related to RLM1. Camalexin was identified as a quantitative co‐dominant resistance factor of Col‐0 origin, but independent of RLM1. RLM1/RLM2 resistance was, however, found to require RAR1 and partially HSP90.1.
External K+ modulates the activity of the Arabidopsis potassium channel SKOR via an unusual mechanism
Authors: Johansson Ingela , Wulfetange Klaas , Porée Fabien , Michard Erwan , Gajdanowicz Pawel , Lacombe Benoît , Sentenac Hervé , Thibaud Jean‐Baptiste , Mueller‐Roeber Bernd , Blatt Michael R. , Dreyer Ingo
Published: March 2006

Plant outward‐rectifying K+ channels mediate K+ efflux from guard cells during stomatal closure and from root cells into the xylem for root–shoot allocation of potassium (K). Intriguingly, the gating of these channels depends on the extracellular K+ concentration, although the ions carrying the current are derived from inside the cell. This K+ dependence confers a sensitivity to the extracellular K+ concentration ([K+]) that ensures that the channels mediate K+ efflux only, regardless of the [K+] prevailing outside. We investigated the mechanism of K+‐dependent gating of the K+ channel SKOR of Arabidopsis by site‐directed mutagenesis. Mutations affecting the intrinsic K+ dependence of gating were found to cluster in the pore and within the sixth transmembrane helix (S6), identifying an ‘S6 gating domain’ deep within the membrane. Mapping the SKOR sequence to the crystal structure of the voltage‐dependent K+ channel KvAP from Aeropyrum pernix suggested interaction between the S6 gating domain and the base of the pore helix, a prediction supported by mutations at this site. These results offer a unique insight into the molecular basis for a physiologically important K+‐sensory process in plants.
Fecundity and spawning of the Atlantic horseshoe crab,Limulus polyphemus, in Pleasant Bay, Cape Cod, Massachusetts, USA
Authors: Leschen Alison S. , Grady Sara P. , Valiela Ivan
Published: March 2006

This study provided the first comprehensive analysis of Atlantic horseshoe crab (Limulus polyphemus) fecundity.Limulusappear to be a determinate spawner, maturing all eggs for the breeding season before spawning begins. On average, larger females held a larger number of eggs (63,500) than smaller females (14,500). By the end of the breeding season there was an average of 11,600 mature eggs per female left undeposited, regardless of female size. Larger females laid a higher percentage of the eggs they contained. Thus they not only contain more eggs, but are more effective at laying them as well. Size of spawning females ranged from about 185–300 mm prosomal width, with by far the highest concentration in the mid‐size ranges. Although on an individual basis large females carry and lay the greatest number of eggs, mid‐size crabs as a group contributed more to the horseshoe crab population in Pleasant Bay because they were more plentiful (net fecundity was highest for mid‐size crabs). These results have implications for the management of this important species, which is harvested for bait, scientific, and biomedical uses. Incorporation of these results into models and other management tools can help predict growth rates, effects of size‐selective harvest, reproductive value, and stable stage distribution of populations.
Latitudinal and bathymetric trends in egg size variation: a new look at Thorson's and Rass's rules
Authors: Laptikhovsky Vladimir
Published: March 2006

The inverse relationship between egg size in marine animals and water temperature was simultaneously described by two outstanding marine scientists: G. Thorson and T.S. Rass. This rule consists of two different phenomena. Thorson's rule describes ecological processes related to changes in larval biology and morphology that are caused by a selective pressure of natural selection on the different types of larval development. It belongs to the realm of macro‐evolution. Rass's rule describes physiological processes within populations and species, and between closely related species. This is not related to changes in reproductive strategy, and therefore belongs to the realm of micro‐evolution and to the early stages of macro‐evolution. Populations begin to produce larger eggs in colder environments because of phenotypic plasticity. Thorson's rule describes temperature‐dependent changes in the relative abundance of small‐ and large‐egged species, whereas Rass's rule describes a temperature‐dependent relative position of both groups within an adaptive range of reproductive strategies.
Assessment of reactions of diverse maize inbred lines to Striga hermonthica (Del.) Benth
Authors: Menkir A.
Published: March 2006

Striga hermonthica is the most widespread and destructive obligate root parasite infecting maize and other cereals in Africa. Maize inbred lines supporting reduced S. hermonthica emergence can form an important basis for developing Striga‐resistant maize cultivars. Twenty new inbred lines selected for field resistance to S. hermonthica, and five inbred checks with known resitance, tolerance and susceptibility reactions to S. hermonthica were evaluated in pots, greenhouse and field experiments under artificial Striga infestation for 3 years. The experiments were conducted to determine the extent of variation in parasite attachment to the roots of these lines and its relationship with emerged Striga plants and other traits. Significant differences (P < 0.0001) were detected among the inbred lines for the numbers of attached and emerged Striga plants and the results were consistent across test environments. Also, the lines exhibited significant differences for Striga damage symptom ratings and other traits recorded in the field. Parasite attachment to the roots was significantly correlated with emerged Striga count in the screenhouse (r = 0.67–0.68, P < 0.001) and in the field (r = 0.82–0.84, P < 0.0001) and with levels of grain yield reduction due to Striga (r = 0.71, P < 0.0001). Regression analysis of the numbers of attached parasites on the first principal component axis scores that integrated several traits recorded in the field was significant (P < 0.0001) and accounted for 62% of the total variation in numbers of attached parasites. The new inbred lines and the resistant inbred check were the least affected by S. hermonthica and exhibited yield losses of 0–37% compared with the yields of the tolerant and the susceptible inbred checks, which were reduced by 40–85%. Sixteen new inbred lines supported significantly fewer attached parasites compared with the susceptible inbred check. Some of these lines also supported significantly fewer emerged parasites and sustained lower damage symptoms and percentage yield losses due to Striga compared with the susceptible inbred check. These inbred lines would be useful in breeding programmes for developing resistant maize cultivars.
Diplotaxis erucoides‐induced cytoplasmic male sterility in Brassica juncea is rescued by the Moricandia arvensis restorer: genetic and molecular analyses
Authors: Bhat S. R. , Vijayan P. , Ashutosh  , Dwivedi K. K. , Prakash S.
Published: March 2006

An alloplasmic cytoplasmic male sterile (CMS) line of Brassica juncea was developed by repeated backcrossing of the sexual hybrid (Diplotaxis erucoides × Brassica rapa) with B. juncea cv. ‘Pusa Bold’. The CMS line is comparable to the B. juncea nuclear donor line for all morphological traits except male fertility. Southern and cleaved amplified polymorphic sequence (CAPS) analyses showed that the CMS line carries organellar genomes from the wild species that differ from the organellar genomes of B. juncea. Northern analysis with three mitochondrial gene probes revealed altered atpα transcription pattern associated with male sterility. The restorer of CMS (Moricandia arvensis) B. juncea was found to restore male fertility to the new CMS system. The mode of fertility restoration was found to be monogenic and gametophytic. The study identified CAPS markers for the psbB gene that could be useful in quick identification of the erucoides CMS line. Broad similarities and important differences observed at the molecular level between M. arvensis and D. erucoides CMS systems of B. juncea are discussed.
A molecular marker linked to the Prv1 gene that confers resistance to Papaya ringspot virus‐type W in melon
Authors: Teixeira A. P. M. , Camargo L. E. A.
Published: March 2006

Papaya ringspot virus‐type W (PRSV‐W) is the most prevalent and important viral pathogen of cucurbits in Brazil. It can be effectively controlled by the incorporation of genetic resistance into susceptible melon cultivars. The present study identified amplified fragment length polymorphic (AFLP) markers linked to the PRSV‐W resistance Prv1 allele. The susceptible yellow‐fleshed melon‐breeding line AF426prv1 and its nearly isogenic‐resistant line AF426Prv1, which carries the Prv1 allele resident in the Indian cantaloupe U.S. Plant Introduction (PI) 180280, were screened for AFLP marker polymorphisms. Of 30 251 AFLP loci, only three were polymorphic between the nearly isogenic lines. Segregation analyses for these three polymorphic markers and the Prv1 allele using a BC1 population of 197 plants indicated close linkage (0.5% recombination frequency) between marker EK190 (HindIII‐CGA and MseI‐GTG; 190 bp) and Prv1. Thus, EK190 might be a useful marker in breeding programmes aiming to develop melon cultivars resistant to PRSV‐W. The other two markers are closely linked to each other, but distantly linked to Prv1.
Genomic in situ hybridization analysis of Brassica napus × Orychophragmus violaceus hybrids and production of B. napus aneuploids
Authors: Hua Y. W. , Li Z. Y.
Published: March 2006

To further utilize the valuable germplasm Orychophragmus violaceus for Brassica genetics and breeding, a B. napus × O. violaceus cross was repeated with embryo rescue. All F1 plants except one B. napus haploid were mixoploids (2n = 17–39 in ovaries) with 2n = 31, 37, 38 and 39 as the maximal chromosome numbers in individuals, but the higher numbers mostly appeared in pollen mother cells (PMCs) with a preponderance of 2n = 30, 37 and 38. Only one chromosome and one chromosome segment of O. violaceus were detected at a low frequency in some ovary cells and PMCs with 2n = 37, 38 and 39 as determined by genomic in situ hybridization analysis. The fatty acid profiles of seeds from the majority of the F1 and F2 plants were similar to those of female B. napus cv. ‘Oro’, but some were obviously different in the percentages of oleic, linoleic and erucic acids, and some F2 plants (2n = 38) with good seed set had high percentages of oleic (>70.0%) or linoleic (to 38.3%) acids and low erucic acid (<1%). Subsequently, many kinds of B. napus aneuploids (2n = 28, 30, 34, 36, 37, 39 and 42), without O. violaceus chromosomes, were derived from F2 progeny and microspores of partial F1 plants. Finally, the cytological mechanisms behind the variations in chromosome numbers were discussed together with the implications of these aneuploids for Brassica genome research and of the plants with altered fatty acid profiles for improving the oil quality of B. napus.
Field analyses of horizontal gene flow among Vigna angularis complex plants
Authors: Yamamoto Y. , Sano C. M. , Tatsumi Y. , Sano H.
Published: March 2006

Recent studies have indicated that spontaneous interspecies crossing commonly occurs among vascular plants, and therefore that horizontal gene flow from transgenic plants into wild relatives is unavoidable. Few surveys, however, have been conducted to determine an actual flow frequency for individual plant species. For the present estimation of gene flow among Vigna angularis complex (small red bean) plants, randomly amplified polymorphic DNA was analysed, the patterns of which differ between a cultivar, var. angularis and its wild counterpart, var. nipponensis. Cultivars and wild‐type plants were planted alternately and approximately 1% of the screened F1 beans of wild type were hybrid. These F1 hybrids were selected, allowed to self to produce F2 beans, and subsequent crossing between the F2 plants and wild type resulted in that 3.7% of the F3 generation possessed DNA fragments specific to the cultivar. These results indicate that gene flow actually occurs among V. angularis complex plants, and that transferred genes might be stably maintained by the offspring. The present observation cannot be directly applied to transgenic plants due to the lack of information as to whether or not artificially introduced genes behave as do native genes after horizontal movement. However, as gene flow is found to be inevitable in this species, specific assessment of whether or not the gene to be introduced confers a significant selective advantage to the host is critical for utilization of genetically modified plants in future.
Indirect activation of neuronal noncapacitative Ca2+ entry is the final step involved in the neurotoxic effect of Tityus serrulatus scorpion β‐toxin
Authors: Grolleau Françoise , Stankiewicz Maria , Kielbasiewicz Ewa , Martin‐Eauclaire Marie‐France , Lavialle Céline , De Vente Jan , Lapied Bruno
Published: March 2006

Interweaving strategies of electrophysiology, calcium imaging and immunocytochemistry bring new insights into the mode of action of the Brazilian scorpion Tityus serrulatusβ‐toxin VII. Pacemaker dorsal unpaired median neurons isolated from the cockroach central nervous system were used to study the effects of toxin VII. In current‐clamp, 50 nm toxin VII produced a membrane depolarization and reduced spiking. At 200 nm, depolarization associated with multiphasic effects was seen. After artificial hyperpolarization, plateau potentials on which spontaneous electrical activity appeared were observed. In voltage clamp, toxin VII induced a negative shift of the voltage dependence of sodium current activation without significant effect on steady‐state inactivation. In addition, toxin VII produced a permanent TTX‐sensitive holding inward current, indicating that background sodium channels were targeted by β‐toxin. Cell‐attached patch recordings indicated that these channels were switched from unclustered single openings to current fluctuating between distinct subconductance levels exhibiting increased open probability and open‐time distribution. Toxin VII also produced a TTX‐sensitive [Ca2+]i rise. Immunostaining with Cav2.2(α1b) antibodies and calcium imaging data obtained with ω‐CgTx GVIA indicated that N‐type high‐voltage‐activated calcium channels initiated calcium influx and were an essential intermediate in the pathway linking toxin VII‐modified sodium channels to the activation of an additional route for calcium entry. By using inhibitors of (i) noncapacitative calcium entry (inhibitor LOE‐908), (ii) NO‐sensitive guanylyl cyclase (ODQ) and (iii) phosphodiesterase 2 (EHNA), together with cGMP antibodies, we demonstrated that noncapacitative calcium entry was the final step in a complex combination of events that was initiated by toxin VII‐alteration of sodium channels and then involved successive activation of other membrane ion channels.
S1P inhibits gap junctions in astrocytes: involvement of Giand Rho GTPase/ROCK
Authors: Rouach Nathalie , Pébay Alice , Même William , Cordier Jocelyne , Ezan Pascal , Etienne Eric , Giaume Christian , Tencé Martine
Published: March 2006

Sphingosine‐1‐phosphate (S1P) is a potent and pleiotropic bioactive lysophospholipid mostly released by activated platelets that acts on its target cells through its own G protein‐coupled receptors. We have previously reported that mouse striatal astrocytes expressed mRNAs for S1P1and S1P3receptors and proliferate in response to S1P. Here, we investigated the effect of S1P on gap junctions. We show that a short‐term exposure of astrocytes to S1P causes a robust inhibition of gap junctional communication, as demonstrated by dye coupling experiments and double voltage‐clamp recordings of junctional currents. The inhibitory effect of S1P on dye coupling involves the activation of both Giand Rho GTPases. Rho‐associated kinase (ROCK) also plays a critical role. The capacity of S1P to activate a Rho/ROCK axis in astrocytes is demonstrated by the typical remodeling of actin cytoskeleton. Connexin43, the protein forming gap junction channels, is a target of the Gi‐ and Rho/ROCK‐mediated signaling cascades. Indeed, as shown by Western blots and confocal immunofluorescence, its nonphosphorylated form increases following S1P treatment and this change does not occur when both cascades are disrupted. This novel effect of S1P may have an important physiopathological significance when considering the proposed roles for astrocyte gap junctions on neuronal survival.
In vivo optical recordings of synaptic transmission and intracellular Ca2+ and Cl– in the superior colliculus of fetal rats
Authors: Sakata Yoshiyuki , Fujioka Takashi , Endoh Hisashi , Nakamura Shoji
Published: March 2006

Although the N‐methyl‐d‐aspartate (NMDA) receptor is known to play a crucial role in activity‐dependent remodeling of synaptic connections in the fetal superior colliculus (SC), its contribution to the electrical activity of fetal SC neurons has not been determined. Furthermore, whether γ‐aminobutyric acid (GABA)‐mediated inhibition occurs either as early as prenatal periods or only after eye opening has been controversial. We therefore performed optical recordings using voltage‐, Ca2+‐ and Cl–‐sensitive fluorescent dyes to analyse synaptic transmission and changes in intracellular Ca2+ and Cl– in the SC of fetal rats that were still connected with the dams by the umbilical cord. Excitatory and inhibitory responses were evoked by focal SC stimulation. The excitatory synaptic responses are composed of early and late components. The early component was mediated by both non‐NMDA and NMDA receptors, whereas the late component occurred mainly via NMDA receptors. Train pulse stimulation at higher currents was required for induction of the inhibition, which was antagonized by bicuculline, and blocking of the GABA‐mediated inhibition by bicuculline uncovered masked excitatory synaptic responses. Focal SC stimulation induced increases in [Cl–]i and [Ca2+]i that were mediated by GABA‐A receptors and mainly by NMDA receptors, respectively. GABA antagonists augmented SC‐induced increases in [Ca2+]i. These results indicate that, in the fetal SC, excitatory and inhibitory synaptic transmissions occur before birth, that the NMDA receptor is a major contributor to excitatory synaptic transmission and increased [Ca2+]i, and that the GABA‐A receptor is already functioning to inhibit excitatory neurotransmission.
Selective impairment of GABAergic synaptic transmission in the flurothyl model of neonatal seizures
Authors: Isaeva Elena , Isaev Dmytro , Khazipov Rustem , Holmes Gregory L.
Published: March 2006

Neonatal seizures can result in long‐term adverse consequences including alteration of seizure susceptibility and impairment in spatial memory. However, little is known about the effects of neonatal seizures on developmental changes occurring in synaptic transmission during the first postnatal weeks. The purpose of the present study was to examine the effect of neonatal seizures on several aspects of γ‐aminobutyric acid (GABA)ergic and glutamatergic synaptic transmission in the developing rat hippocampus. Flurothyl was used to induce multiple recurrent seizures in rat pups during the first postnatal days. Whole‐cell patch‐clamp recordings from the hippocampal CA3 pyramidal cell and extracellular recordings from the CA3 pyramidal cell layer were made in slice preparations. In rats that experienced neonatal seizures the amplitude of spontaneous inhibitory postsynaptic currents at P15–17 was decreased by 27% compared with controls, whereas neither frequency nor the kinetic properties were altered. Neonatal seizures did not affect the timing of the developmental switch in the GABAA signaling from excitatory to inhibitory. None of the studied parameters of glutamatergic postsynaptic currents was different between the flurothyl and control groups, including the amplitude and frequency of the spontaneous excitatory postsynaptic currents, the ratio of the amplitudes and frequencies of the α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) and N‐methyl‐d‐aspartate (NMDA)‐mediated spontaneous postsynaptic currents, and the kinetics of AMPA and NMDA mediated postsynaptic currents in the age groups P8–10 and P15–17. We suggest that the selective depression of the amplitude of GABAergic synaptic responses may contribute to the adverse neurological and behavioral consequences that occur following neonatal seizures.
What drives elevational patterns of diversity? A test of geometric constraints, climate and species pool effects for pteridophytes on an elevational gradient in Costa Rica
Authors: Kluge Jürgen , Kessler Michael , Dunn Robert R.
Published: March 2006

Aim  We studied pteridophyte species richness between 100 m and 3400 m along a Neotropical elevational gradient and tested competing hypotheses for patterns of species richness.

Location  Elevational transects were situated at Volcán Barva in the Braulio Carrillo National Park and La Selva Biological Station (100–2800 m) and Cerro de la Muerte (2700–3400 m), both on the Atlantic slope of Costa Rica, Central America.

Method  We analysed species richness on 156 plots of 20 × 20 m and measured temperature and humidity at four elevations (40, 650, 1800 and 2800 m). Species richness patterns were regressed against climatic variables (temperature, humidity, precipitation and actual evapotranspiration), regional species pool, area and predicted species number of a geometric null model (the mid‐domain effect, MDE).

Results  The species richness of the 484 recorded species showed a hump‐shaped pattern with elevation with a richness peak at mid‐elevations (c. 1700 m). The MDE was the single most powerful explanatory variable in linear regression models, but species richness was also associated strongly with climatic variables, especially humidity and temperature. Area and species pool were associated less strongly with observed richness patterns.

Main conclusions  Geometric models and climatic models exclusive of geometric constraints explained comparable amounts of the elevational variation in species richness. Discrimination between these two factor complexes is not possible based on model fits. While overall fits of geometric models were high, large‐ and small‐ranged species were explained by geometric models to different extents. Species with narrow elevational ranges clustered at both ends of the gradient to a greater extent than predicted by the MDE null models used here. While geometric models explained much of the pattern in species richness, we cannot rule out the role of climatic factors (or vice versa) because the predicted peak in richness from geometric models, the empirical peak in richness and the overlap in favourable environmental conditions all coincide at middle elevations. Mid‐elevations offer highest humidity and moderate temperatures, whereas at high elevations richness is reduced due to low temperatures, and at low elevations by reduced water availability due to high temperatures.
Don't Talk About Pink Elephants!
Authors: Lane Liane Wardlow , Groisman Michelle , Ferreira Victor S.
Published: March 2006

Speakers' descriptions sometimes inappropriately refer to information known only to them, thereby “leaking” knowledge of that private information. We evaluated whether speakers can explicitly control such leakage in light of its communicative consequences. Speakers described mutually known objects (e.g., a triangle) that had size-contrasting matches that were privileged to the speakers (e.g., a larger triangle visible to the speakers only), so that use of a contrasting adjective (e.g., small) involved referring to the privileged information. Half the time, speakers were instructed to conceal the identity of the privileged object. If speakers can control their leaked references to privileged information, this conceal instruction should make such references less likely. Surprisingly, the conceal instruction caused speakers to refer to privileged objects more than they did in the baseline condition. Thus, not only do speakers have difficulty not leaking privileged information, but attempts to avoid such leakage only make it more likely.
Spatial Distance and Mental Construal of Social Events
Authors: Fujita Kentaro , Henderson Marlone D. , Eng Juliana , Trope Yaacov , Liberman Nira
Published: March 2006

Construal-level theory proposes that increasing the reported spatial distance of events leads individuals to represent the events by their central, abstract, global features (high-level construal) rather than by their peripheral, concrete, local features (low-level construal). Results of two experiments indicated that participants preferred to identify actions as ends rather than as means to a greater extent when these actions occurred at a spatially distant, as opposed to near, location (Study 1), and that they used more abstract language to recall spatially distant events, compared with near events (Study 2). These findings suggest that spatially distant events are associated with high-level construals, and that spatial distance can be conceptualized as a dimension of psychological distance.
Social Discounting
Authors: Jones Bryan , Rachlin Howard
Published: March 2006

The amount of money a person was willing to forgo in order to give $75 to another person decreased as a hyperbolic function of the perceived social distance between them. Similar hyperbolic functions have previously been shown to describe both time and probability discounting.
The Impact of Emotion on Perception
Authors: Zeelenberg René , Wagenmakers Eric-Jan , Rotteveel Mark
Published: March 2006

Recent studies have shown that emotionally significant stimuli are often better identified than neutral stimuli. It is not clear, however, whether these results are due to enhanced perceptual processing or to a bias favoring the identification of emotionally significant stimuli over neutral stimuli. The present study used a two-alternative forced-choice perceptual identification task to disentangle the effects of bias and enhanced processing. We found that emotionally significant targets were better identified than neutral targets. In contrast, the emotional significance of the foil alternative had no effect on performance. The present results support the hypothesis that perceptual encoding of emotionally significant stimuli is enhanced.
Domain Specificity in Experimental Measures and Participant Recruitment
Authors: Hanoch Yaniv , Johnson Joseph G. , Wilke Andreas
Published: March 2006

We challenge the prevailing notion that risk taking is a stable trait, such that individuals show consistent risk-taking/aversive behavior across domains. We subscribe to an alternative approach that appreciates the domain-specific nature of risk taking. More important, we recognize heterogeneity of risk profiles among experimental samples and introduce a new methodology that takes this heterogeneity into account. Rather than using a convenient subject pool (i.e., university students), as is typically done, we specifically targeted relevant subsamples to provide further validation of the domain-specific nature of risk taking. Our research shows that individuals who exhibit high levels of risk-taking behavior in one content area (e.g., bungee jumpers taking recreational risks) can exhibit moderate levels in other risky domains (e.g., financial). Furthermore, our results indicate that risk taking among targeted subsamples can be explained within a cost-benefit framework and is largely mediated by the perceived benefit of the activity, and to a lesser extent by the perceived risk.
Temporally Unfolding Neural Representation of Pictorial Occlusion
Authors: Rauschenberger Robert , Liu Taosheng , Slotnick Scott D. , Yantis Steven
Published: March 2006

The human visual system possesses a remarkable ability to reconstruct the shape of an object that is partly occluded by an interposed surface. Behavioral results suggest that, under some circumstances, this perceptual process (termed amodal completion) progresses from an initial representation of local image features to a completed representation of a shape that may include features that are not explicitly present in the retinal image. Recent functional magnetic resonance imaging (fMRI) studies have shown that the completed surface is represented in early visual cortical areas. We used fMRI adaptation, combined with brief, masked exposures, to track the amodal completion process as it unfolds in early visual cortical regions. We report evidence for an evolution of the neural representation from the image-based feature representation to the completed representation. Our method offers the possibility of measuring changes in cortical activity using fMRI over a time scale of a few hundred milliseconds.
Market Sentiment and Macroeconomic Fluctuations under Pegged Exchange Rates
Authors: AGÉNOR PIERRE‐RICHARD
Published: March 2006

The effects of an adverse change in market sentiment, defined as a temporary increase in the premium faced by domestic borrowers on world financial markets, are studied in an intertemporal optimizing framework with imperfect capital mobility. Firms' demands for working capital are financed by bank credit. The shock leads to a rise in domestic interest rates, capital outflows and a drop in official reserves, a reduction in bank deposits and loans, a contraction in output, and an increase in unemployment. These predictions are consistent with Argentina's economic downturn in the immediate aftermath of the Mexican peso crisis of December 1994.
Clinical Characteristics of Tension‐Type Headache and Migraine in Adolescents: A Student‐Based Study
Authors: Karlı Necdet , Akgöz Semra , Zarifoğlu Mehmet , Akış Nalan , Erer Sevda
Published: March 2006

Background and objectives.—Adolescent headaches, particularly migraine, might present with different features from adult headaches. The objectives of this study were to investigate the characteristics of tension‐type headache and migraine, to find the sensitivity and specificity of the diagnostic criteria of the IHS classification according to age and gender.

Methods.—A multistep, stratified, cluster sampling method was used for subject selection. The estimated sample size was 2387. The study was conducted in two phases: the questionnaire and the face to face interview phases. During the semistructured interview, a clinical diagnosis has been made and clinical characteristics have been recorded.

Results.—All headaches fulfilled the criteria of duration. The most common feature of migraine was moderate to severe (92.4%), pulsating pain (79.2%). For ETTH, bilateral localization (91.3%) and mild to moderate pain intensity (90.6%) were the most common features. Younger adolescents showed mixed headache characteristics. Highest sensitivities for migraine were duration (100%), moderate to severe pain (92.4%), and pulsating quality of pain (79.2%). Vomiting, trigger factors food and alcohol had a high specificity for migraine.

Conclusions.—Our data strongly support continuum hypothesis. In early adolescence headaches might present with mixed headache characteristics. Age and gender have some influence on headache characteristics, particularly on migraine. The sensitivity and specificity of case definition criteria of ICHD‐2 for adolescent migraine is moderate and need to be reconsidered.
Characteristic and Overlapping Features of Migraine and Tension‐Type Headache
Authors: Turkdogan Dilsad , Cagirici Sultan , Soylemez Didem , Sur Haydar , Bilge Cevdet , Turk Ulku
Published: March 2006

Objective.—This epidemiological survey was conducted to investigate comprehensive characteristic and overlapping features of migraine and tension‐type headache (TTH) disorders classified based on International Classification of Headache Disorders‐II.

Methods.—The stratified cohort of this study was composed of 2504 schoolchildren aged 10 to 17 years. A 38‐item questionnaire inquiring all characteristic features of primary headache syndromes mandatory for classification was applied to selected 483 children with recurrent headache in the last 6 months.

Results.—Migraine was diagnosed in 227 (47.0%) of 483 children and TTH in 154 (31.9%). Out of 125 children with definite migraine, 73 (58.4%) reported tension‐type symptoms and 94 (68.1%) of 138 children with definite TTH reported migraine‐type symptoms. Pressing pain (21%) and lack of aggravation of pain by physical activity (34%) were the major tension‐type features in patients with migraine. Throbbing quality (43%) and aggravation by physical activity (30%) determined the main migraine‐type features in patients with TTH.

Conclusion.—The frequent co‐occurrence of migraine and TTH symptoms suggests the presence of a common pathogenesis.
Prevention of Migraine With Olmesartan in Patients With Hypertension/Prehypertension
Authors: Charles James A. , Jotkowitz Seymour , Byrd Lawrence H.
Published: March 2006

Objective.—To explore the effects of olmesartan on frequency and severity of migraine attacks in patients with comorbid hypertension and prehypertension.

Background.—A randomized, double‐blind, placebo‐controlled, crossover study with a total of 60 patients has demonstrated the efficacy and safety of the angiotensin II receptor blocker candesartan in migraine prophylaxis. We study the potential efficacy and tolerability of olmesartan in preventing migraine in patients with hypertension and prehypertension.

Design/Methods.—Twenty‐four adults, aged 27 through 76, with either hypertension or prehypertension, were included in this open‐label study. Participants suffered from migraines (diagnosed according to International Headache Society classifications) for at least 3 months. Patients were treated with 10 to 40 mg of olmesartan per various observational periods of at least 3 months. Frequency and severity were recorded by office visits or by telephonic interview.

Results.—Patients reported an 82.5% average reduction in the frequency of migraine attacks. Patients also experienced a 45% average reduction in the severity of migraine attacks measured on a numeric pain scale of 1 to 10. The only undesired effect was dizziness or presyncope. No serious adverse events occurred and no adverse event caused a premature termination. Two patients had no reduction in headache frequency, intensity, and blood pressure.

Conclusions.—The favorable results and low rate of adverse effects, in this open migraine prevention study in patients with hypertension or prehypertension, are similar to results of the randomized, double‐blind, placebo‐controlled, crossover study in patients taking candesartan. Olmesartan shows a potential as an effective and well‐tolerated migraine prophylactic agent for patients with comorbid hypertension and prehypertension.
Chronic Long‐Standing Headache due to Neurocysticercosis
Authors: Finsterer Josef , Li Mei , Rasmkogeler Kartrin , Auer Herbert
Published: March 2006

A 35‐year‐old Chinese woman presented with a 26‐year history of persistent headache, relieved only by diuretics. Characteristic CT findings, peripheral eosinophilia, lymphocytic CSF pleocytosis, elevated CSF IgG, positive oligoclonal bands, antibody‐positive ELISA, and Western blot results with Taenia solium antigen, and a favorable response to albendazole led to the diagnosis of neurocysticercosis.
Assessment of Atrial Regional Wall Motion Using Strain Doppler Imaging During Biatrial Pacing in the Bradycardia‐Tachycardia Syndrome
Authors: MATSUMOTO KATSUMI , ISHIKAWA TOSHIYUKI , SUMITA SHINICHI , MATSUSHITA KOHEI , INOUE NORIKO , KOBAYASHI TSUKASA , UCHINO KAZUAKI , KIMURA KAZUO , UMEMURA SATOSHI
Published: March 2006

Introduction: Biatrial pacing is expected to have preventive effects on atrial fibrillation.

Methods: We evaluated atrial regional wall motion by strain Doppler imaging (SDI) in 6 patients (62.5 ± 11.3 [SD] years), who suffered from atrial fibrillation, with an implanted biatrial pacemaker. SDI was performed and atrial regional wall motion was estimated during biatrial (BiA) and right atrial appendage (RAA) pacing.

Results: There was no significant difference in the interval from the pacing spike to the peak strain of the atrium in the lateral right atrium (LRA) between BiA and RAA pacing. However, there was a significant difference in the septal atrium (SA) between BiA and RAA pacing (225.0 ± 19.9 vs 267.2 ± 15.7 ms, P < 0.0001) and in the lateral left atrium (LLA) between BiA and RAA pacing (216.7 ± 21.6 vs 275.0 ± 16.2 ms, P < 0.0001). There were significant differences in the time difference of peak strain between BiA and RAA pacing in each atrial segment (LRA‐AS: 2.2 ± 5.9 vs 45.0 ± 11.9 ms, P = 0.0016, SA‐LLA: −8.3 ± 5.5 vs 7.8 ± 2.7 ms, P < 0.0011, LRA‐LLA: −6.1 ± 3.9 vs 52.8 ± 13.2 ms, P = 0.0002). There was no significant difference in the interval from the pacing spike to the inflection point of atrial strain (S‐I) of LRA. However, there were significant differences in S‐I of SA (83.9 ± 24.1 vs 129.9 ± 30.6 ms, P = 0.0086) and LLA (102.2 ± 37.9 vs 166.1 ± 13.4 ms, P = 0.0028).

Conclusion: BiA pacing improved the synchronicity of regional wall motion of both atrium.