bluuebunny/crossref_metadata_2025 huggingface dataset:
X chromosome map at 75-kb STS resolution, revealing extremes of recombination and GC content.
Authors: Nagaraja R , MacMillan S , Kere J , Jones C , Griffin S , Schmatz M , Terrell J , Shomaker M , Jermak C , Hott C , Masisi M , Mumm S , Srivastava A , Pilia G , Featherstone T , Mazzarella R , Kesterson S , McCauley B , Railey B , Burough F , Nowotny V , D'Urso M , States D , Brownstein B , Schlessinger D
Published: June 2007

A YAC/STS map of the X chromosome has reached an inter-STS resolution of 75 kb. The map density is sufficient to provide YACs or other large-insert clones that are cross-validated as sequencing substrates across the chromosome. Marker density also permits estimates of regional gene content and a detailed comparison of genetic and physical map distances. Five regions are detected with relatively high G + C, correlated with gene richness; and a 17-Mb region with very low recombination is revealed between the Xq13.3 [XIST] and Xq21.3 XY homology loci.
One-megabase sequence analysis of the human immunoglobulin lambda gene locus.
Authors: Kawasaki K , Minoshima S , Nakato E , Shibuya K , Shintani A , Schmeits J L , Wang J , Shimizu N
Published: June 2007

A total of 1,025,415 bases of nucleotide sequence, including the entire human immunoglobulin lambda gene locus has been determined. This is the largest contiguous human DNA sequence ever published. The sequence data revealed the organization of 36 potentially active V lambda gene segments, 33 pseudogene segments, and seven J lambda-C lambda gene segments. Among these 69 functional or nonfunctional V lambda gene segments, 32 were newly discovered. These V lambda gene segments are located within five gene-rich clusters and are divided into five clans based on sequence identity. Five potentially active nonimmunoglobulin genes were also detected within the lambda gene locus, and two other genes were observed in the upstream region. Sequence organization suggests that large DNA duplications diversified the germ-line repertoire of the V lambda gene segments.
Rapid sequence analysis of gene trap integrations to generate a resource of insertional mutations in mice.
Authors: Townley D J , Avery B J , Rosen B , Skarnes W C
Published: June 2007

Gene trapping in murine embryonic stem cells is a proven method for the simultaneous identification and mutation of genes in the mouse. Gene trap vectors are designed to detect insertions within genes through the production of a fusion mRNA transcript, making the identification of the endogenous gene possible by 5' rapid amplification of cDNA ends (RACE). Although the amplification of specific cDNAs can be achieved rapidly, cloning and screening of informative-sized cDNAs has proven to be time consuming. To eliminate the need for cloning, we have developed a method for solid-phase sequencing of 5' RACE products. More than 150 independent gene trap cell lines were analyzed, and sequence information was obtained for every line successfully amplified by RACE. With the vector used in this study, 40% of the cell lines were found to contain properly spliced gene trap events. The remaining lines were either spliced inefficiently or contained deletions of the vector. These results highlight the advantage of sequencing gene trap integrations before further characterization. This work now paves the way for large-scale gene trap screens in mice and should greatly accelerate the functional analysis of the mammalian genome.
Long-term potentiation and evidence for novel synaptic association in CA1 stratum oriens of rat hippocampus.
Authors: Otani S , Connor J A , Levy W B
Published: June 2007

In CA1 stratum oriens of hippocampal slices, a robust long-term potentiation (LTP) induced by tetanic stimulation (20 pulses at 100 Hz, 10 trains delivered at 0.1 Hz) was accompanied by a slowly developing potentiation in a second, untetanized pathway. N-methyl-D-aspartate (NMDA) receptor antagonist DL-2-amino-5-phosphonovaleric acid (D-APV, 50 or 100 microM) reduced the homosynaptic LTP by 80% but failed to affect heterosynaptic LTP. The metabotropic receptor antagonist DL-2-amino-3-phosphonopropionic acid DL-AP3, 300 microM) or (+)-alpha-methyl-4-carboxyphenylglycine (MCPG, 500 microM), applied with DL-APV, further reduced homosynaptic LTP and blocked heterosynaptic LTP. The inhibitor of Ca(2+)-induced Ca2+ release dantrolene (20 microM), also applied with DL-APV, blocked both components of LTP. Importantly, when low-frequency test stimulation (0.017 Hz) to the untetanized, heterosynaptic pathway was interrupted for 30 min after homosynaptic tetanization, heterosynaptic LTP did not develop. These results demonstrate homosynaptic and heterosynaptic LTP inductions in stratum oriens of the area CA1 and suggest that the heterosynaptic LTP is induced by NMDA-independent, novel associative processes between tetanized and untetanized pathways.
A critical period of protein kinase activity after tetanic stimulation is required for the induction of long-term potentiation.
Authors: Huber K M , Mauk M D , Thompson C , Kelly P T
Published: June 2007

A critical period of protein kinase activity required for the induction of long-term potentiation (LTP) was determined in area CA1 or hippocampal slices using the broad-range and potent protein kinase inhibitors K-252a and staurosporine. As reported previously, K-252a and staurosporine blocked LTP induction when applied before, during, and after high-frequency stimulation (HFS). In contrast, K-252a did not block LTP when applied only before and during HFS and washed out immediately after HFS. K-252a and staurosporine both attenuated LTP magnitude when applied immediately after or as late as 5 min after HFS. However, K-252a applications beginning 30-45 min after HFS did not affect LTP expression significantly. K-252a had no detectable effect on isolated N-methyl-D-aspartate (NMDA) receptor-mediated EPSPs but significantly inhibited the in situ phosphorylation of specific hippocampal proteins (synapsin I, MARCKS, and B-50). In addition, K-252a attenuated 4 beta-phorbol-12,13-dibutyrate (PDBu)-enhanced synaptic transmission. Our results indicate that there is a critical period of protein kinase activity required for LTP induction that extends for approximately 20 min after HFS. In addition, our results suggest that protein kinase activity during and immediately after HFS is not sufficient for LTP induction. These results provide new information about the mechanisms that underlie LTP induction and expression and provide evidence for persistent and/or Ca(2+)-independent protein kinase activity involvement in LTP.
A biochemist's view of long-term potentiation.
Authors: Roberson E D , English J D , Sweatt J D
Published: June 2007

This review surveys the molecular mechanisms of long-term potentiation (LTP) from the point of view of a biochemist. On the basis of available data, LTP in area CA1 of the hippocampus is divided into three phases--initial, early, and late--and the mechanisms contributing to the induction and expression of each phase are examined. We focus on evidence for the involvement of various second messengers and their effectors as well as the biochemical strategies employed in each phase to convert a transient signal into a lasting change in the neuron. We also consider, from a biochemical perspective, the implications of a multiphase model for LTP.
Transient expression of c-Fos in rat amygdala during training is required for encoding conditioned taste aversion memory.
Authors: Lamprecht R , Dudai Y
Published: June 2007

Local microinjection into rat amygdala of phosphorothioate modified oligodeoxynucleotides (ODNs) antisense to c-fos several hours before conditioned taste aversion (CTA) training impaired taste aversion memory tested 3-5 days after conditioning. In contrast, injection of the antisense ODNs several days before training, before testing, or into the basal ganglia, or injection of c-fos sense ODNs, had no effect on CTA memory. Inhibition of translation by local microinjection of anisomycin into the amygdala shortly before as well as during CTA training, but not several days before training or shortly before testing, also impaired CTA memory. We conclude that translation in general, and c-Fos translation in particular, in the amygdala during or immediately after CTA training is essential for encoding taste aversion memory.
Conditioned visual flight orientation in Drosophila: dependence on age, practice, and diet.
Authors: Guo A , Li L , Xia S Z , Feng C H , Wolf R , Heisenberg M
Published: June 2007

Orientation preferences for visual patterns can be conditioned in tethered flies (Drosophila melanogaster) at the flight simulator. In a reversal conditioning procedure using heat as reinforcement, flies can be trained to successively prefer different flight orientations with respect to the patterns. As in many learning paradigms, conditioned responses are highly variable. Although during training most flies reliably avoid the heat and the corresponding flight orientations, in subsequent learning tests without heat some show no consistent preference for the permissive orientations. We have started to investigate the interindividual differences in learning performance and describe here three significant variables: the age of the animals, their experience in the flight simulator prior to the experiment, and the composition of the fly food. Flies learn more reliably at 3-4 days than at 1-2 days of age but learning indices do not increase further in even older flies. Learning is improved if flies are allowed to become familiar with the flight simulator before the start of the conditioning procedure. Most important, poor nutrition causes complete amnesia within three or four generations. The reverse shift from poor to nutritious food restores learning ability with an even longer delay.
Modification of hippocampal synaptic proteins by nitric oxide-stimulated ADP ribosylation.
Authors: Sullivan B M , Wong S , Schuman E M
Published: June 2007

Nitric oxide has been shown to be an important neuronal signaling molecule that participates in both behavioral and synaptic plasticity. To better understand the potential mechanisms by which NO regulates synaptic function, the ability of NO to stimulate the modification of synaptic proteins by ADP ribosylation was examined. Two NO donors, sodium nitroprusside and 3-morpholinosydnonimine, stimulated the ADP ribosylation of proteins at apparent molecular masses of 42, 48, 51, 54, and 74 kD in hippocampal synaptosomes. This stimulation was likely owing to the production of NO by the donors; ADP ribosylation was not stimulated by non-NO decomposition products of sodium nitroprusside, and quenching of superoxide anion did not inhibit Sin-1-induced ADP ribosylation. Experiments using NAD+ that was radiolabeled on the nicotinamide moiety demonstrated that the modification of proteins of molecular masses of 30, 33, and 38 kD are not true ADP ribosylation, whereas labeling of the 42-, 48-, 51-, 54-, and 74-kD proteins likely represent ADP ribosylation. Some of the substrates were brain specific (54 and 74 kD), whereas others (42 and 51 kD) were present in multiple nonbrain tissues.
The learning-related activity that develops in the pontine nuclei during classical eye-blink conditioning is dependent on the interpositus nucleus.
Authors: Clark R E , Gohl E B , Lavond D G
Published: June 2007

A growing body of research now implicates the cerebellum in the formation and storage of the critical neural plasticity that subserves the classically conditioned eye-blink response. Previous anatomical, physiological, and behavioral research suggests that auditory-conditioned stimulus information is routed to the cerebellum by the pontine nuclei. However, it has also been observed from multiple unit recordings that some populations of pontine cells, in addition to showing auditory-evoked responses, also show changes in activity that is learning-related. It is unknown whether this learning-related activity is generated by the pontine cells or whether it is generated by some other structure and projected to the pontine nuclei. Because the cerebellum has been implicated in the formation of the essential plasticity that subserves this learned behavior, we examined how multiple unit recordings of learning-related activity within the pontine nuclei are affected by reversible inactivation of the interpositus nucleus of the cerebellum. The results indicated clearly that when the interpositus nucleus was inactivated, the learning-related activity in the pontine nuclei was abolished completely and the auditory stimulus-evoked activity was unaffected. In contract, when the facial nucleus was inactivated, both the auditory stimulus and the learning-related activity were still present. These results indicate that the learning-related activity exhibited by some populations of pontine nuclei cells is dependent on the interpositus nucleus and may represent feedback from the cerebellum.
Persistent phosphorylation parallels long-term desensitization of cerebellar purkinje cell AMPA-type glutamate receptors.
Authors: Nakazawa K , Mikawa S , Ito M
Published: June 2007

This study is aimed at testing the hypothesis that sustained phosphorylation underlies long-term desensitization of AMPA receptors, which is thought to be the mechanism of long-term synaptic depression in cerebellar Purkinje cells (PCs). We induced long-term desensitization of AMPA receptors in rat cerebellar slices by (1) a 4-min bath application of quisqualate (0.1 mM) or (2) a 15-min bath application of a protein kinase C (PKC) activator, phorbol-12,13-diacetate (0.5 microM) or -dibutyrate (0.6 microM), followed by a 4-min AMPA (0.1 mM) application. In slices so treated, labeling with an antibody (12P3) against a peptide corresponding to part of AMPA receptor subunit GluR2 including serine 696 and phosphorylated at this serine site revealed phosphorylation of the AMPA receptors in PC dendrites that was sustained for at least 1 hr. At an early phase, within 20 min after the chemical stimulation, the phosphorylation was resistant to an Ca2+ chelator (BAPTA-AM), a metabotropic glutamate receptor antagonist (MCPG), and a PKC inhibitor (calphostin C), whereas at a late phase, 30 min or more after the chemical stimulation, it was blocked by these reagents similarly to long-term desensitization of AMPA receptors. Taken together with data obtained previously using different protocols of chemical stimulation, the present results strongly support the above-mentioned hypothesis.
Local dendritic Ca2+ signaling induces cerebellar long-term depression.
Authors: Eilers J , Takechi H , Finch E A , Augustine G J , Konnerth A
Published: June 2007

The coordinated activity of large numbers of adjacent parallel fiber synapses elevate calcium concentration locally in small regions of Purkinje cell dendrites. Such activity has also been reported to produce long-term depression of parallel fiber synaptic transmission. We have examined the relationship between these two events by combining patch clamp measurements of parallel fiber synaptic transmission with confocal microscopic imaging of the local calcium signals. We find that patterns of parallel fiber activity capable of evoking long-term depression invariably cause increases in Purkinje cell calcium concentration that are very spatially restricted. These results suggest that one function of the local dendritic calcium signals is to induce long-term depression of parallel fiber synapses.
Impaired capacity of cerebellar patients to perceive and learn two-dimensional shapes based on kinesthetic cues.
Authors: Shimansky Y , Saling M , Wunderlich D A , Bracha V , Stelmach G E , Bloedel J R
Published: June 2007

This study addresses the issue of the role of the cerebellum in the processing of sensory information by determining the capability of cerebellar patients to acquire and use kinesthetic cues received via the active or passive tracing of an irregular shape while blindfolded. Patients with cerebellar lesions and age-matched healthy controls were tested on four tasks: (1) learning to discriminate a reference shape from three others through the repeated tracing of the reference template; (2) reproducing the reference shape from memory by drawing blindfolded; (3) performing the same task with vision; and (4) visually recognizing the reference shape. The cues used to acquire and then to recognize the reference shape were generated under four conditions: (1) "active kinesthesia," in which cues were acquired by the blindfolded subject while actively tracing a reference template; (2) "passive kinesthesia," in which the tracing was performed while the hand was guided passively through the template; (3) "sequential vision," in which the shape was visualized by the serial exposure of small segments of its outline; and (4) "full vision," in which the entire shape was visualized. The sequential vision condition was employed to emulate the sequential way in which kinesthetic information is acquired while tracing the reference shape. The results demonstrate a substantial impairment of cerebellar patients in their capability to perceive two-dimensional irregular shapes based only on kinesthetic cues. There also is evidence that this deficit in part relates to a reduced capacity to integrate temporal sequences of sensory cues into a complete image useful for shape discrimination tasks or for reproducing the shape through drawing. Consequently, the cerebellum has an important role in this type of sensory information processing even when it is not directly associated with the execution of movements.
Role of cerebellum in adaptive modification of reflex blinks.
Authors: Pellegrini J J , Evinger C
Published: June 2007

We investigated the involvement of the cerebellar cortex in the adaptive modification of corneal reflex blinks and the regulation of normal trigeminal reflex blinks in rats. The ansiform Crus I region contained blink-related Purkinje cells that exhibited a complex spike 20.4 msec after a corneal stimulus and a burst of simple spike activity correlated with the termination of orbicularis oculi activity. This occurrence of the complex spike correlated with trigeminal sensory information associated with the blink-evoking stimulus, and the burst of simple spike activity correlated with sensory feedback about the occurrence of a blink. Inactivation of the inferior olive with lidocaine prevented all complex and significantly reduced simple spike modulation of blink-related Purkinje cells, but did not alter orbicularis oculi activity evoked by corneal stimulation. In contrast, both acute and chronic lesions of the cerebellar cortex containing blink-related Purkinje cells blocked adaptive increases in orbicularis oculi activity of the lid ipsilateral but not contralateral to the lesion. These data are consistent with the hypothesis that the cerebellum is part of a trigeminal reflex blink circuit. Changes in trigeminal signals produce modifications of the cerebellar cortex, which in turn, reinforce or stabilize modifications of brainstem blink circuits. When the trigeminal system does not attempt to alter the magnitude of trigeminal reflex blinks, cerebellar input has little or no effect on reflex blinks.
Vision affects mushroom bodies and central complex in Drosophila melanogaster.
Authors: Barth M , Heisenberg M
Published: June 2007

The brain of Drosophila is structurally altered by sensory stimuli that the flies receive during their adult life. Size and fiber number of the mushroom bodies, central complex, and optic lobes are influenced by social, spatial, or olfactory cues. Recently, the optic lobes have been shown to depend on the light regime that flies experience. Structural plasticity in the brain is thought to be a correlate of functional adaptations and long-term memory. We therefore extend our investigation of volume changes to the calyces of the mushroom bodies and the central complex. We show that rearing flies in constant light for 4 days increases the volume of both structures by up to 15% compared to rearing them in total darkness. Much of this difference develops during the first day. The effect of light is not hormonally mediated, as monocularly deprived flies develop a smaller ipsilateral calyx. Mutant analysis suggests that light generates its effects through known visual pathways. In contrast to the optic lobes, in the calyx and central complex structural changes can be linked to cAMP signaling, as in the mutants dunce1 and amnesiac1 no volume differences are observed. Surprisingly, the mutant rutabaga1 shows a prominent light-dependent volume increase in the calyx and central complex, dissociating structural from behavioral plasticity. In complete darkness wild-type flies grow larger calyces under crowded conditions in their normal culture vials than if kept in small groups on fresh food. This stimulating effect of crowding is not observed in any of the cAMP mutants, including rutabaga1.
Differential patterns of c-fos mRNA expression in amygdala during successive stages of odor discrimination learning.
Authors: Hess U S , Gall C M , Granger R , Lynch G
Published: June 2007

Expression of the activity-dependent gene c-fos was used to assess relative levels of neuronal activation in the amygdala and related structures of rats at different stages of odor discrimination learning. In situ hybridization was used to evaluate c-fos mRNA content within the amygdalar subdivisions, the bed nucleus of the stria terminalis, and the hippocampus. After initial exploration of the test apparatus, c-fos mRNA levels were increased in the medial and, to lesser extent, basolateral subdivisions and remained low in the central division. The balance of amygdala to hippocampal labeling favored hippocampus. Rats engaged in familiar nose-poke responses had comparably elevated labeling in the medial and basolateral divisions and low labeling densities in the central division. The ratio of hippocampal to amygdala labeling was at control levels. Rats required to switch from ad libitum responding to cued responding to odors had high basolateral to medial labeling ratios. This was in marked contrast to the medial dominance found in control and exploration rats. Hybridization was substantially more dense in basolateral amygdala than in hippocampal CA1; this imbalance was unique to the group required to form first associations between odors and rewards. Rats performing an overtrained odor discrimination had the least differentiation between amygdalar subdivisions of any behavioral group. The hippocampus-to-amygdala labeling ratio favored hippocampus and was nearly identical to the ratio in exploration rats. These results demonstrate that the balance of activity within the between limbic structures shifts according to behavioral demands. It is suggested that the balances reflect the availability of pertinent afferent cues, interactions between hippocampus and the extended amygdala, and relative levels of activity in the diffuse projections to the limbic system.
Reaction time distributions across normal forgetting: searching for markers of memory consolidation.
Authors: Reber P J , Alvarez P , Squire L R
Published: June 2007

Volunteers studied pictures of objects and were then tested for yes/no recognition at 10 min and 1 week after learning (experiment 1), or at 10 min and 4 months after learning (experiment 2). Because the gradual consolidation of long-term memory is thought to occur across this time scale (weeks and months), the reaction time distributions of successfully retrieved items were analyzed in an attempt to detect markers of consolidation. At each retention interval, reaction times for items retrieved successfully were well fit by a model that assumed a single underlying distribution. No evidence for a bimodal distribution of reaction times was observed. Furthermore, there was no evidence that some small subset of items was actually retrieved faster after a long retention interval than after a short interval. The results are consistent with the idea that consolidation works not to increase memory trace strength but to change the nature of memory storage. This process occurs during the course of normal forgetting and may not be observable in the behavior of normal memory.
Impaired declarative memory for emotional material following bilateral amygdala damage in humans.
Authors: Adolphs R , Cahill L , Schul R , Babinsky R
Published: June 2007

Everyday experience suggests that highly emotional events are often the most memorable, an observation supported by psychological and pharmacological studies in humans. Although studies in animals have shown that nondeclarative emotional memory (behaviors associated with emotional situations) may be impaired by lesions of the amygdala, little is known about the neural underpinnings of emotional memory in humans, especially in regard to declarative memory (memory for facts that can be assessed verbally). We investigated the declarative memory of two rare patients with selective bilateral amygdala damage. Both subjects showed impairments in long-term declarative memory for emotionally arousing material. The data support the hypothesis that the human amygdala normally enhances acquisition of declarative knowledge regarding emotionally arousing stimuli.
Memory for temporal order of new and familiar spatial location sequences: role of the medial prefrontal cortex.
Authors: Chiba A A , Kesner R P , Gibson C J
Published: June 2007

Rats with medial prefrontal cortex or sham control lesions were tested on an eight-arm radial maze task to examine memory for the temporal order of a variable and a constant sequence of spatial locations as a function of temporal distance. During the study phase of each trial, rats were allowed to visit each of eight arms once in an order that was randomly selected or fixed for that trial. The test phase required the rats to choose which of two arms occurred earlier in the sequence of arms visited during the study phase. The arms selected as test arms varied according to temporal distance (0, 2, 4, or 6) or the number of arms that occurred between the two test arms in the study phase. For the variable sequences based on new information, control rats showed an increasing temporal distance function. Relative to control rats, medial prefrontal cortex-lesioned rats displayed a temporal order memory deficit across all distances. For the constant sequence based on familiar information, control rats performed well across all distances. Relative to controls, the medial prefrontal cortex-lesioned rats displayed a performance deficit. The results support the idea that the medial prefrontal cortex contributes to mnemonic operations associated with temporal order for new and familiar spatial location information.
Visual space from visual motion: turn integration in tethered flying Drosophila.
Authors: Wolf R , Heisenberg M
Published: June 2007

Organisms navigating by path integration need to continuously measure their forward movement and their angular orientation with respect to an external reference. How they do it is little understood. Tethered flies at the flight simulator "navigate" in an artificial visual landscape without forward movement. They can return to a previously held orientation if the panorama provides a singularity (landmark) as reference. Surprisingly, in a regularly striped drum without singularities, they can use a temporal cue instead. In this experiment the arena is illuminated with only one color that is either green or blue. The arena is virtually divided into four quadrants. Whenever a quadrant boundary moves past an arbitrary point, the color of the arena light changes. When a fly is heated with one color it acquires a preference for the other one. Subsequently, it avoids the borders toward the potentially 'hot' quadrants even without touching them. The only way to achieve this is by turn integration, that is, by adding and subtracting all the turns it performs once it crosses the border. The color switch defining the border crossing resets the turn integrator, using the orientation of the arena at this moment as reference. In contrast, landmarks or, if it were available, the skylight compass enable the fly to establish by pattern learning any orientation as a reference. If the reference orientation coincides with the desired orientation, that is, if the animal stores the pattern while being oriented toward the goal, it can maintain its orientation without recourse to turn integration (which may be error prone).
Behavioral manipulation of retrieval in a spatial memory task for Drosophila melanogaster.
Authors: Wustmann G , Heisenberg M
Published: June 2007

A paradigm for operant conditioning of freely walking single Drosophila flies has been described previously. A fly can be conditioned to avoid one side of a small test chamber if the chamber is heated whenever the fly enters this side. In a subsequent memory test without heat the fly continues to avoid the previously heat-associated side. In this experimental design one cannot exclude that flies mark the heated side by an odor that they subsequently avoid during the test. As a final proof for associative learning in the present experiment, flies are trained in one chamber and tested for learning in another, similar one. Handling in the transfer experiment interferes with memory display, even if the fly is returned to the old chamber instead of a new one. Memory can be reactivated, however, by subjecting the fly to an additional brief training (priming), which is too short to establish significant learning in naive flies. For efficient priming, heat has to be applied to the same side as during training in the old chamber. Only then the fly subsequently shows a side preference and avoids the side of the new chamber, which in the old one had been associated with heat. The two chambers are similar but not identical The transfer experiment therefore raises the question as to what the flies use as spatial reference during training and test. In the light, they can be shown to orientate according to visual landmarks associated with the chamber. In complete darkness, where training and memory scores do not differ from those in the light, they are assumed to use a combination of tactile and idiothetic information for orienting.
Identification of specific mRNAs affected by treatments producing long-term facilitation in Aplysia.
Authors: Zwartjes R E , West H , Hattar S , Ren X , Noel F , Nuñez-Regueiro M , MacPhee K , Homayouni R , Crow M T , Byrne J H , Eskin A
Published: June 2007

Neural correlates of long-term sensitization of defensive withdrawal reflexes in Aplysia occur in sensory neurons in the pleural ganglia and can be mimicked by exposure of these neurons to serotonin (5-HT). Studies using inhibitors indicate that transcription is necessary for production of long-term facilitation by 5-HT. Several mRNAs that change in response to 5-HT have been identified, but the molecular events responsible for long-term facilitation have not yet been fully described. To detect additional changes in mRNAs, we investigated the effects of 5-HT (1.5 hr) on levels of mRNA in pleural-pedal ganglia using in vitro translation. Four mRNAs were affected by 5-HT, three of which were identified as calmodulin (CaM), phosphoglycerate kinase (PGK), and a novel gene product (protein 3). Using RNase protection assays, we found that 5-HT increased all three mRNAs in the pleural sensory neurons. CaM and protein 3 mRNAs were also increased in the sensory neurons by sensitization training. Furthermore, stimulation of peripheral nerves of pleural-pedal ganglia, an in vitro analog of sensitization training, increased the incorporation of labeled amino acids into CaM, PGK, and protein 3. These results indicate that increases in CaM, PGK, and protein 3 are part of the early response of sensory neurons to stimuli that produce long-term facilitation, and that CaM and protein 3 could have a role in the generation of long-term sensitization.
Analysis of sequence-dependent interactions between transient calcium and transmitter stimuli in activating adenylyl cyclase in Aplysia: possible contribution to CS--US sequence requirement during conditioning.
Authors: Abrams T W , Yovell Y , Onyike C U , Cohen J E , Jarrard H E
Published: June 2007

An important recent insight in a number of neurobiological systems is that during learning, individual dually regulated proteins with associative properties function as critical sites of stimulus convergence. During conditioning in Aplysia, the Ca2+ /calmodulin-sensitive adenylyl cyclase (AC) in mechanosensory neurons serves as a molecular site of interaction between Ca2+ and serotonin [5-hydroxytryptamine (5-HT)]-two signals that represent the CS and US in these cells. Conditioning requires that the CS and US be paired within a narrow time window and in the appropriate sequence. AC shows an analogous sequence preference: It is more effectively activated when a pulse of Ca2+ precedes a pulse of 5-HT than when the 5-HT precedes Ca2+. One mechanism that contributes to this sequence preference is that Ca2+/calmodulin binding to AC accelerates the rate of AC activation by receptor-Gs. We have identified two additional properties of AC activation that would cause pairing with Ca2+ preceding 5-HT to be more effective than simultaneous pairing or pairing with the reciprocal sequence: (1) Activation of Aplysia AC by a Ca2+ pulse rose with a delay compared with activation by a 5-HT pulse. (2) A late pulse of Ca2+, which arrived after 5-HT, acted, via calmodulin, to accelerate the decay of AC activation by receptor-Gs. Together, these activation properties of AC may contribute to the CS-US sequence requirement of classical conditioning.
Perforant path activation modulates the induction of long-term potentiation of the schaffer collateral--hippocampal CA1 response: theoretical and experimental analyses.
Authors: Levy W B , Desmond N L , Zhang D X
Published: June 2007

In one computational model of hippocampal function, the entorhinal cortical input to CA1 is hypothesized to play a key role in the ability of CA1 to decode CA3 recodings. Here, we develop a modification of this CA1 decoder hypothesis that is applicable to several computational theories of hippocampal function, and then we electrophysiologically investigate one assumption of this new hypothesis. First, using biologically realistic estimates, we calculate that CA3-induced CA1 excitation is too high and that inhibition plausibly plays a role in this CA1 decoder model. Thus motivated, we turn to a physiological demonstration to substantiate the plausibility of the proposed mechanism. Using the rat hippocampal slice, we examine an interlaminar interaction between the distal perforant path input to hippocampal CA1 stratum moleculare and the more proximal Schaffer collateral input to stratum radiatum. Perforant path activation provides sufficient inhibition to block homosynaptic long-term potentiation elicited by a suitably strong stratum radiatum input. For this interlaminar interaction to be most effective, perforant path activation must both precede and follow Schaffer collateral activation. Perforant path-evoked inhibition in CA1 can thus serve as a viable mechanism in the learned decoder theory of hippocampal CA1.
A survey of rate of victimization and attitudes towards physical violence among school‐aged children in Turkey
Authors: Deveci S. E. , Acik Y. , Ayar A.
Published: June 2007

Background  Violence of any type is a serious issue in the lives of many children from all racial, cultural and economic backgrounds, and is a topic of enormous societal concern in any society. The purpose of this study was to examine the rate of exposure to violence as victims, and attitudes towards physical violence among school‐aged children in eastern Turkey.

Methods  All the basic education schools in Elazig, a typical eastern Anatolian city, were included. A total of 3725 fifth and sixth graders were asked to answer survey questions about the rate of physical violence exposure in their everyday lives and whether they thought the violence was an ‘acceptable’ behaviour.

Results  The mean age of participants was 12.8 years with 46.8% boys and 53.2% girls, and their socio‐economic status ranged from low‐income to upper middle class. Seventy‐four per cent of school‐aged children reported exposure to at least one case of physical violence in their lives, and 43.4% reported experiencing physical violence within previous 12 months. Higher rates of exposure to physical violence were reported by boys than girls (P = 0.0001). Of the victims, 33.8% regarded physical violence as an acceptable or inevitable way of solution or responding to life events.

Conclusions  Results from the self‐report of the receiving end of violent behaviours indicate that physical violent victimization is at an alarmingly high rate among children of eastern Turkey, and a significant per cent of these victims approves violence as a way of solution.
Involving families who have deaf children using a Family Needs Survey: a multi‐agency perspective
Authors: Dalzell J. , Nelson H. , Haigh C. , Williams A. , Monti P. ,   [West Cheshire Hearing Advisory and Support Team (HAST)]
Published: June 2007

Background  Meeting the needs of deaf children and their families is multidisciplinary. Models of multi‐agency working are diverse, and there is little evidence on outcome for family and child. Effective collaboration is an essential part of multi‐agency working, and how this is achieved is an area that warrants research.

Methods  An approach was developed to identify family needs using a need identification tool called a Family Needs Survey (FNS) in conjunction with a multi‐agency meeting. The FNS was introduced in a pilot study to involve parents of deaf children with services and to identify their needs from their perspective.

Results and conclusions  A clear pathway was determined for application of the FNS. A model of multi‐agency working was developed that involves families directly with different services at one time. Outcomes were measured by uptake of the FNS, parental attendance at multi‐agency meetings, and completion of a parent evaluation questionnaire. Discussion of the FNS at a multi‐agency meeting facilitates communication between professionals and between professionals and parents. There is some evidence that the FNS may be a useful tool. The majority of parents completed a FNS before multi‐agency meetings and have indicated they are happy to share the information with other professionals
Observations towards early-type stars in the ESO-POP Survey – II. Searches for intermediate- and high-velocity clouds
Authors: Smoker J. V. , Hunter I. , Kalberla P. M. W. , Keenan F. P. , Morras R. , Hanuschik R. , Thompson H. M. A. , Silva D. , Bajaja E. , Poppel W. G. L. , Arnal M.
Published: June 2007

We present Ca ii K and Ti ii optical spectra of early-type stars taken mainly from the ultraviolet and visual echelle spectrograph (UVES) Paranal Observatory Project, plus H i 21-cm spectra, from the Vila-Elisa and Leiden-Dwingeloo Surveys, which are employed to obtain distances to intermediate- and high-velocity clouds (IHVCs). H i emission at a velocity of −117 km s−1 towards the sightline HD 30677 () with column density ∼1.7 × 1019 cm−2 has no corresponding Ca ii K absorption in the UVES spectrum, which has a signal-to-noise ratio (S/N) of 610 per resolution element. The star has a spectroscopically determined distance of 2.7 kpc, and hence sets this as a firm lower distance limit towards Anti-Centre cloud ACII. Towards another sightline (HD 46185 with ), H i at a velocity of +122 km s−1 and column density of 1.2 × 1019 cm−2 is seen. The corresponding Ca ii K spectrum has a S/N of 780, although no absorption is observed at the cloud velocity. This similarly places a firm lower distance limit of 2.9 kpc towards this parcel of gas that may be an intermediate-velocity (IV) cloud. The lack of IV Ca ii absorption towards HD 196426 () at a S/N of 500 reinforces a lower distance limit of ∼700 pc towards this part of complex gp, where the H i column density is 1.1 × 1019 cm−2 and velocity is +78 km s−1. Additionally, no IV Ca ii is seen in absorption in the spectrum of HD 19445, which is strong in H i with a column density of 8 × 1019 cm−2 at a velocity of ∼−42 km s−1, placing a firm although uninteresting lower distance limit of 39 pc to this part of IV South. Finally, no high-velocity Ca ii K absorption is seen towards HD 115363 () at a S/N of 410, placing a lower distance of ∼3.2 kpc towards the HVC gas at velocity of ∼+224 km s−1 and H i column density of 5.2 × 1019 cm−2. This gas is in the same region of the sky as complex WE (Wakker 2001), but at higher velocities. The non-detection of Ca ii K absorption sets a lower distance of ∼3.2 kpc towards the HVC, which is unsurprising if this feature is indeed related to the Magellanic System.
The light stress‐induced protein ELIP2 is a regulator of chlorophyll synthesis in Arabidopsis thaliana
Authors: Tzvetkova‐Chevolleau Tzvetelina , Franck Fabrice , Alawady Ali E. , Dall’Osto Luca , Carrière Frédéric , Bassi Roberto , Grimm Bernhard , Nussaume Laurent , Havaux Michel
Published: June 2007

The early light‐induced proteins (ELIPs) belong to the multigenic family of pigment‐binding light‐harvesting complexes. ELIPs accumulate transiently and are believed to play a protective role in plants exposed to high levels of light. Constitutive expression of the ELIP2 gene in Arabidopsis resulted in a marked reduction of the pigment content of the chloroplasts, both in mature leaves and during greening of etiolated seedlings. The chlorophyll loss was associated with a decrease in the number of photosystems in the thylakoid membranes, but the photosystems present were fully assembled and functional. A detailed analysis of the chlorophyll‐synthesizing pathway indicated that ELIP2 accumulation downregulated the level and activity of two important regulatory steps: 5‐aminolevulinate synthesis and Mg‐protoporphyrin IX (Mg‐Proto IX) chelatase activity. The contents of glutamyl tRNA reductase and Mg chelatase subunits CHLH and CHLI were lowered in response to ELIP2 accumulation. In contrast, ferrochelatase activity was not affected and the inhibition of Heme synthesis was null or very moderate. As a result of reduced metabolic flow from 5‐aminolevulinic acid, the steady state levels of various chlorophyll precursors (from protoporphyrin IX to protochlorophyllide) were strongly reduced in the ELIP2 overexpressors. Taken together, our results indicate that the physiological function of ELIPs could be related to the regulation of chlorophyll concentration in thylakoids. This seems to occur through an inhibition of the entire chlorophyll biosynthesis pathway from the initial precursor of tetrapyrroles, 5‐aminolevulinic acid. We suggest that ELIPs work as chlorophyll sensors that modulate chlorophyll synthesis to prevent accumulation of free chlorophyll, and hence prevent photooxidative stress.
Intravenous immunoglobulin as an adjunct to plasma exchange for the treatment of chronic thrombotic thrombocytopenic purpura
Authors: Moore J. C. , Arnold D. M. , Leber B. F. , Clare R. , Molnar G. J. , Kelton J. G.
Published: June 2007

Thrombotic thrombocytopenic purpura (TTP) is a life‐threatening disease. Therapeutic plasma exchange (TPE) is the most effective therapy; however, despite TPE, about one‐third of TTP patients will relapse. A subset of patients with TTP has antibodies to ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) and may become resistant to conventional treatments. We describe a patient with TTP and high‐titre anti‐ADAMTS13 antibodies who developed a chronic, relapsing course of TTP despite frequent TPE. Once adjuvant treatment with intravenous immunoglobulin (IVIG) was added, remission was achieved. Even during remission, anti‐ADAMTS13 antibodies remained elevated. We conclude that IVIG may sustain remission in some patients with chronic, relapsing TTP.
Genetic analysis of racing performance in Irish greyhounds
Authors: Täubert H. , Agena D. , Simianer H.
Published: June 2007

The aim of this study was to analyse racing performance data in Irish greyhounds with regard to genetic and environmental variation. Estimation of heritabilities for racing time (RT) and ranking, and the prediction of breeding values for all greyhounds in the investigated data were carried out. Data from 42 785 races in Ireland in the years 2000–2003 were available. These results were obtained from 42 880 greyhounds on 20 race tracks over a distance of 480 m. Three traits were analysed, RT, ranking and a scaled logarithmic function for RT (ART), which was used to adjust racing time to be normally distributed. The data were analysed with a bivariate animal model. The estimated heritabilities were moderate for RT (0.31) and ART (0.38), but very low for ranking (0.10). The repeatabilities were 0.56 (RT), 0.51 (ART) and 0.13 (ranking). The genetic correlations were very high, 0.99 (RT–ranking) and 0.96 (ART–ranking), while the phenotypic correlation was lower, 0.60 (RT–ranking) and 0.62 (ART–ranking). The genetic trend for the traits as well as the phenotypic change of the average RT was positive.
Possibility of selecting racehorses on jumping ability based on their steeplechase race results in France, the United Kingdom and Ireland
Authors: Bokor Á. , Blouin C. , Langlois B.
Published: June 2007

The aim of this study was to detect Thoroughbred mare families and sire lines, in France, in the United Kingdom and Ireland, whose offspring may be successful in steeplechase races and can be recommended therefore for sport horse breeding. Race results were collected from all steeplechase races in these countries between 1998 and 2003, which contained the results of 17 355 horses from 12 861 dams and 2452 sires. In France, non‐Thoroughbred horses were also included in the analysis because they race and mate together with Thoroughbreds. Performance was measured with two criteria: earnings and ranks after mathematical transformation. The effects of year, sex, age and race were considered as fixed, animal, permanent environment and maternal environment as random. Precorrection for the effect of race was done to avoid computational difficulties. Maternal environmental components for ranks were 0.02 in France and zero in the United Kingdom and Ireland. Estimated heritabilities for the ranking criteria were 0.18 (repeatability 0.33) in France and 0.06 (repeatability 0.19) in the United Kingdom and Ireland. The high genetic correlation between the two criteria of measurement (0.94 and 0.97 respectively) gives the opportunity to choose the most suitable criteria for breeding value estimation. The ranking value, after statistical normalization has a great advantage for comparison between the countries.
Genetic parameters for feed efficiency traits and their relationships with growth and carcass traits in Duroc pigs
Authors: Hoque M.A. , Suzuki K. , Kadowaki H. , Shibata T. , Oikawa T.
Published: June 2007

Genetic parameters for feed efficiency traits of 380 boars and growth and carcass traits of 1642 pigs (380 boars, 868 gilts and 394 barrows) in seven generations of Duroc population were estimated. Feed efficiency traits included the feed conversion ratio (FCR), and nutritional (RFInut), phenotypic (RFIphe) and genetic (RFIgen) residual feed intake. Growth and carcass traits were the age to reach 105‐kg body weight (A105), loin eye muscle area (EMA), backfat (BF), intra‐muscular fat (IMF) and meat tenderness. The mean values for RFIphe and RFIgen were close to zero and for RFInut was negative. All the measures of feed efficiency were moderately heritable (h2 = 0.31, 0.38, 0.40 and 0.27 for RFInut, RFIphe, RFIgen and FCR respectively). The heritabilities for all growth and carcass traits were moderate (ranged from 0.37 to 0.45), except for BF, which was high (0.72). The genetic correlations of RFIphe and RFIgen with A105 were positive and high. Measures of RFI were correlated negatively with EMA. BF was more strongly correlated with measures of RFI (rg  0.73) than with FCR (rg = 0.52). Selection for daily gain, EMA, BF and IMF caused favourable genetic changes in feed efficiency traits. Results of this study indicate that selection against either RFIphe or RFIgen would give a similar correlated response in carcass traits.