bluuebunny/crossref_metadata_2025 huggingface dataset:
pH‐dependent stability of the human α‐lactalbumin molten globule state: Contrasting roles of the 6—120 disulfide and the β‐subdomain at low and neutral pH
Authors: Horng Jia‐Cherng , Demarest Stephen J. , Raleigh Daniel P.
Published: June 2003

Many proteins are capable of populating partially folded states known as molten globule states. α‐Lactalbumin forms a molten globule under a range of conditions including low pH (the A‐state) and at neutral pH in the absence of Ca2+with modest amounts of denaturant. The A‐state is the most thoroughly characterized and thought to mimic a kinetic intermediate populated during refolding at neutral pH. We demonstrate that the properties and interactions that stabilize the A‐state and the pH 7 molten globule of human α‐lactalbumin differ. The unfolding of the wild‐type protein is compared to the unfolding of a variant that lacks the 6120 disulfide bond and to an autonomously folded peptide construct that we have previously shown represents the minimum core structure of the A‐state of human α‐lactalbumin. Studies conducted at pH 2 and 7 show that the disulfide makes little contribution to the stability of the molten globule at pH 7 but is important at pH 2. In contrast, the β‐subdomain of the protein is less important at pH 2 than at pH 7. The role of helix propensity in stabilizing the different forms of the molten globule state is examined and it is shown that it cannot account for the differences. The strikingly different behavior observed at pH 2 and 7 indicates that the A‐state may not be a rigorous mimic of the folding intermediate populated at pH 7. Proteins 2003;52:193–202. © 2003 Wiley‐Liss, Inc.
The unswapped chain of bovine seminal ribonuclease: Crystal structure of the free and liganded monomeric derivative
Authors: Sica Filomena , Di Fiore Anna , Zagari Adriana , Mazzarella Lelio
Published: June 2003

Bovine seminal ribonuclease, a homodimeric enzyme joined covalently by two interchain disulphide bonds, is an equilibrium mixture of two conformational isomers, M×M and M=M. The major form, M×M, whose crystal structure has been previously determined at 1.9 Å resolution, presents the swapping of the N‐terminal segments (residues 1–15) and composite active sites formed by residues of different chains. The three‐dimensional domain swapping does not occur in the M=M form. The different fold of each N‐terminal tail is directed by the hinge loop (residue 16–22) connecting the swapping domain to the body of the protein. Reduction and alkylation of interchain disulphide bridges produce a monomeric derivative and a noncovalent swapped dimer, which are both active. The free and nucleotide‐bound forms of the monomer have been crystallized at an alkaline pH and refined at 1.45 and 1.65 Å resolution, respectively. In both cases, the N‐terminal fragment is folded on the main body of the protein to produce an intact active site and a chain architecture very similar to that of bovine pancreatic ribonuclease. In this new fold of the seminal chain, the hinge loop is disordered. Despite the difference between the tertiary structure of the monomer and that of the chains in the M×M form, the active sites of the two enzymes are virtually indistinguishable. Furthermore, the structure of the liganded enzyme represents the first example of a ribonuclease complex studied at an alkaline pH and provides new information on the binding of a nucleotide when the catalytic histidines are deprotonated. Proteins 2003;52:263–271. © 2003 Wiley‐Liss, Inc.
Possible locally driven folding pathways of TC5b, a 20‐residue protein
Authors: Nikiforovich Gregory V. , Andersen Niels H. , Fesinmeyer R. Matthew , Frieden Carl
Published: June 2003

A novel computational procedure for modeling possible locally driven folding pathways by stepwise elongations of the peptide chain was successfully applied to TC5b, a 20‐residue miniprotein. Systematic exploration of the possible locally driven pathways showed that the Trp‐cage structure of TC5b could be obtained by stepwise elongation starting from the noncentral local nucleation centers preexisting in the unfolded state of TC5b. The probable locally driven folding pathway starts with folding of α‐helical fragment 4‐9, followed by formation of the proper three‐dimensional structure of fragment 4‐12, and then 4‐18. Accordingly, the Trp‐cage‐forming interactions emerge successively, first Trp6–Pro12, then Trp6–Pro18, and then Trp6–Tyr3. The Trp‐cage‐like structures of TC5b found in this study by independent energy calculations are in excellent agreement with the NMR experimental data. The same procedure rationalizes the incomplete Trp‐cage formation observed for two analogs of TC5b. Generally, the success of this novel approach is encouraging and provides some justification for the use of computational simulations of locally driven protein folding. Proteins 2003;52:292–302. © 2003 Wiley‐Liss, Inc.
Effective energy function for proteins in lipid membranes
Authors: Lazaridis Themis
Published: June 2003

A simple extension of the EEF1 energy function to heterogeneous membrane‐aqueous media is proposed. The extension consists of (a) development of solvation parameters for a nonpolar phase using experimental data for the transfer of amino acid side‐chains from water to cyclohexane, (b) introduction of a heterogeneous membrane‐aqueous system by making the reference solvation free energy of each atom dependent on the vertical coordinate, (c) a modification of the distance‐dependent dielectric model to account for reduced screening of electrostatic interactions in the membrane, and (d) an adjustment of the EEF1 aqueous model in light of recent calculations of the potential of mean force between amino acid side‐chains in water. The electrostatic model is adjusted to match experimental observations for polyalanine, polyleucine, and the glycophorin A dimer. The resulting energy function (IMM1) reproduces the preference of Trp and Tyr for the membrane interface, gives reasonable energies of insertion into or adsorption onto a membrane, and allows stable 1‐ns MD simulations of the glycophorin A dimer. We find that the lowest‐energy orientation of melittin in bilayers varies, depending on the thickness of the hydrocarbon layer. Proteins 2003;52:176–192. © 2003 Wiley‐Liss, Inc.
Identification of the domains for DNA binding and transactivation function of C protein from bacteriophage Mu
Authors: Paul Bindu Diana , Kanhere Aditi , Chakraborty Atanu , Bansal Manju , Nagaraja Valakunja
Published: June 2003

The C protein, a middle gene product of bacteriophage Mu, is the determinant of the transition from middle to late gene expression. C activates transcription from four late gene promoters, Plys, PI, PP, and Pmom by binding to a site overlapping their −35 elements. Site‐specific, high‐affinity binding of C to its recognition sequence results in both axial and torsional distortion of DNA at Pmom, which appears to play a role in recruitment of RNA polymerase to the promoter for mom gene transactivation. To identify the regions of C protein important for its function, deletion and site‐directed mutagenesis were carried out. We demonstrate here that a helix‐turn‐helix (HTH) motif located toward the carboxy terminal end of the protein is the DNA‐binding domain and amino acid residues involved in transactivation overlap the HTH motif. Mutagenesis studies also aided in the identification of the region important for dimerization. Structure‐based sequence alignment and molecular modeling in conjunction with mutational analysis suggest that the HTH motif is part of a three‐helix bundle, with remarkable similarity to paired (prd), a developmental regulatory protein from Drosophila. Additional key residues identified in the model to be crucial for C protein structure and DNA binding were shown to be important by mutagenesis. These results provide a structural framework for C function and insight into the mechanism of transactivation at the mom promoter. Proteins 2003;52:272–282. © 2003 Wiley‐Liss, Inc.
Crystal structure of a putative CN hydrolase from yeast
Authors: Kumaran Desigan , Eswaramoorthy Subramaniam , Gerchman Sue Ellen , Kycia Helen , Studier F. William , Swaminathan Subramanyam
Published: June 2003

The crystal structure of a yeast hypothetical protein with sequence similarity to CN hydrolases has been determined to 2.4 Å resolution by the multiwavelength anomalous dispersion (MAD) method. The protein folds as a four‐layer αββα sandwich and exists as a dimer in the crystal and in solution. It was selected in a structural genomics project as representative of CN hydrolases at a time when no structures had been determined for members of this family. Structures for two other members of the family have since been reported and the three proteins have similar topology and dimerization modes, which are distinct from those of other αββα proteins whose structures are known. The dimers form an unusual eight‐layer αββα:αββα structure. Although the precise enzymatic reactions catalyzed by the yeast protein are not known, considerable information about the active site may be deduced from conserved sequence motifs, comparative biochemical information, and comparison with known structures of hydrolase active sites. As with serine hydrolases, the active‐site nucleophile (cysteine in this case) is positioned on a nucleophile elbow. Proteins 2003;52:283–291. © 2003 Wiley‐Liss, Inc.
Side‐chain dynamics and protein folding
Authors: Kussell Edo , Shimada Jun , Shakhnovich Eugene I.
Published: June 2003

The processes by which protein side chains reach equilibrium during a folding reaction are investigated using both lattice and all‐atom simulations. We find that rates of side‐chain relaxation exhibit a distribution over the protein structure, with the fastest relaxing side chains located in positions kinetically important for folding. Traversal of the major folding transition state corresponds to the freezing of a small number of side chains, belonging to the folding nucleus, whereas the rest of the protein proceeds toward equilibrium via backbone fluctuations around the native fold. The postnucleation processes by which side chains relax are characterized by very slow dynamics and many barrier crossings, and thus resemble the behavior of a glass. Proteins 2003;52:303–321. © 2003 Wiley‐Liss, Inc.
Fish assemblage response to recent mitigation of a channelized warmwater stream
Authors: Raborn Scott. W. , Schramm Harold L.
Published: June 2003

Various designs of low‐head dams are used to rehabilitate streams or forestall upstream channel incision after channelization. We report on the efficacy of using notched sills and grade control structures (GCS) to restore the fish assemblage in Luxapallila Creek, Mississippi. We tested the null hypotheses that habitat variables and species richness, evenness, and assemblage structure would not differ among: (1) a channelized segment with no modifications; (2) a channelized segment mitigated by the installation of sills and GCS; (3) a segment upstream of the installations and undergoing channel incision; and (4) an unaltered segment. Although habitat variables changed, neither species richness, evenness, nor fish assemblage structure differed between mitigated and channelized segments with both exhibiting less richness and different assemblage structures than the unaltered segment. Lack of differences in species richness between the incised and unaltered segments suggest that the GCS may have halted the negative effects of upstream channel incision before species were extirpated. Conspicuous habitat differences between the altered (channelized and mitigated) and unaltered segments were lack of backwaters and canopy coverage and finer substrates in the altered segments. Our results suggest a more comprehensive rehabilitation strategy is required in Luxapallila Creek. Published in 2003 by John Wiley & Sons, Ltd.
Survival of salmonid eggs in a degraded gravel‐bed stream: effects of groundwater–surface water interactions
Authors: Malcolm Iain A. , Youngson Alan F. , Soulsby Chris
Published: June 2003

The effect of hyporheic water quality on developing salmonids was assessed between spawning and hatch. Results from a low‐lying degraded agricultural catchment (Newmills Burn) were compared with those from a near‐pristine upland spawning stream (Girnock Burn), providing a set of comparisons beyond the range of hyporheic conditions present in the Newmills Burn. It was demonstrated that hyporheic water quality in the Newmills Burn varied temporally and spatially as a consequence of variable fluxes of chemically reduced groundwater through heterogeneous drift deposits. Mortality rates from samplers located within artificial redds ranged from 0 to 100% and showed a clear negative relationship with mean dissolved oxygen (DO) concentrations (r2 = 0.85, P < 0.01). Where embryo mortality was less than 100%, low DO appeared to affect rates of embryo development. Embryos exposed to lower DO concentrations were observed to have a higher percentage mass of yolk sac than those developing in more favourable conditions. The chemical characteristics of hyporheic water in the stream were indicative of the mixing of longer residence regional groundwater with local surface water at shallow depths. The hyporheic water of the Girnock Burn approximated closely to that of surface water suggesting a local origin. Hyporheic water quality affects egg survival and may limit recruitment when egg deposition is marginal or inadequate. A consideration of hyporheic dynamics and groundwater–stream interactions should form part of channel modification or restoration works in salmonid spawning streams. Copyright © 2003 John Wiley & Sons, Ltd.
Suitable habitats for 0‐group fish in rehabilitated floodplains along the lower River Rhine
Authors: Grift R. E. , Buijse A. D. , Van Densen W. L. T. , Machiels M. A. M. , Kranenbarg J. , Klein Breteler J. G. P. , Backx J. J. G. M.
Published: June 2003

The suitability of rehabilitated floodplains along the lower River Rhine for rheophilic cyprinids was assessed by investigating the spatial distribution of 0‐group fish among, and within, three newly created secondary channels, an oxbow lake reconnected at its downstream end and several existing groyne fields. Fish were sampled during April through September 1997–1999 with seine nets and trawls and, for each sample, the habitat (physical environment) was characterized (flow, depth, substrate and inundated terrestrial vegetation). The new water bodies provide more suitable habitats for 0‐group fish than the groyne fields. Their beneficial value differs, however, between reproductive guilds and depends on the morphological and hydrological conditions. Total fish density increased along a gradient of decreasing water flow whereas the proportion of rheophilic species (Barbus barbus, Gobio gobio, Leuciscus idus and Aspius aspius) decreased. Flow velocity and water depth were the most important factors determining habitat utilization. Rheophilic fish were spatially separated from eurytopic fish (e.g. Abramis brama, Rutilus rutilus and Stizostedion lucioperca). During flood events, inundated terrestrial vegetation was an important habitat for the larvae of all species. To enhance the riverine fish community, floodplain water bodies should have complex shorelines, and a high variability of flow velocities. Their slopes should be moderate to maximize the probability of terrestrial vegetation getting inundated during spring and summer. Future management of similar floodplains should focus on more diverse and accessible aquatic habitats to increase overall fish species diversity, since different types of water body clearly have complementary values. Copyright © 2003 John Wiley & Sons, Ltd.
Asymmetric modulation of a catecholamine‐regulated protein in the rat brain, following quinpirole administration
Authors: Gabriele Joseph , Culver Kirsten , Sharma Sunjay , Zhang Bingjun , Szechtman Henry , Mishra Ram
Published: June 2003

We previously reported a brain‐specific 40 kDa catecholamine‐regulated protein (CRP40) that binds dopamine (DA) and related catecholamines. CPR40 shares significant sequence homology with human heat shock protein (Hsp70), GRP78/BIP, and human #BQ24193 protein. Recent studies with the DA D2 receptor antagonist, haloperidol, demonstrated a significant increase in expression of CRP40 in the striatum (STR). The objective of the present study was to investigate CRP40 expression in various brain regions following treatments with the DA D2/D3 receptor agonist quinpirole (QNP) in rats and examine possible relationships between neurochemical parameters and locomotor activity. Rats received injections of either QNP (0.5 mg/kg, for 27 days every third day) or saline (SAL) and their locomotor activities were measured for 90 min after each injection. At injection 9, QNP‐treated rats showed locomotor activity that was significantly greater than SAL controls (F(2,28) = 3.88, P < 0.05, Duncan's multiple range test, P < 0.05). Neurochemically, acute QNP‐treated rats demonstrated significant differential expression of CRP40 in the left/right prefrontal cortex (PFC) relative to SAL‐treated rats (–17.76 ± 2.10%, −10.35 ± 1.23%, P < 0.001). Chronic QNP significantly decreased CRP40 expression in the STR, ventral tegmental area (VTA), and left/right PFC (–24.85± 2.10%, −18.15 ± 5.64%, −49.13 ± 7.05%, −25 ± 3.63%, P < 0.001). Finally, chronic QNP treatment resulted in a significant increase in CRP40 levels in the nucleus accumbens (NA) (+39.32 ± 7.00%, P < 0.001). Heat shock protein (i.e., Hsp70 or Hsc70) expression remained unaltered following QNP treatment. Since QNP is a DA D2/D3 agonist, alterations in CRP40 expression following QNP treatment suggest the protein's function in dopaminergic neurotransmission. Synapse 49:261–269, 2003. © 2003 Wiley‐Liss, Inc.
Dopamine displaces [3H]domperidone from high‐affinity sites of the dopamine D2 receptor, but not [3H]raclopride or [3H]spiperone in isotonic medium: Implications for human positron emission tomography
Authors: Seeman Philip , Tallerico Teresa , Ko Françoise
Published: June 2003

Because the high‐affinity state of the dopamine D2 receptor, D2High, is the functional state of the receptor, has a role in demarcating typical from atypical antipsychotics, and is markedly elevated in amphetamine‐sensitized rats, it is important to have a method for the convenient detection of this state by a ligand. The present data show that, in contrast to [3H]spiperone or [3H]raclopride, [3H]domperidone labels D2High sites in the presence of isotonic NaCl in either striatum or cloned D2Long receptors, yielding a dopamine dissociation constant (1.75 nM) in agreement with that found with [3H]dopamine. Increased labeling of D2High sites occurred with [3H]domperidone after severe disruption of the cells, suggesting that [3H]domperidone has better access to the D2 receptor from the cytoplasmic aspect of the cell membrane. The density of the [3H]domperidone‐labeled D2 receptors was the same as that of the [3H]raclopride‐labeled D2 receptors, but twice the density of [3H]spiperone sites for human cloned D2Long receptors, compatible with the monomer‐dimer concept of the D2 receptor. [3H]domperidone readily labels the D2High sites in postmortem human brain homogenates. Although [3H]spiperone or [3H]raclopride can occupy D2High sites, the inability of 1–10 nM dopamine to displace these ligands under isotonic conditions suggests that these ligands may not be suitable for monitoring the physiological high‐affinity state of the dopamine D2 receptor by means of [11C]methylspiperone or [11C]raclopride in humans. Synapse 49:209–215, 2003. © 2003 Wiley‐Liss, Inc.
How is firing activity of substantia nigra cells regulated? Relevance of pattern‐code in the basal ganglia
Authors: Rodríguez Manuel , Pereda Ernesto , González Julián , Abdala Patricio , Obeso Jose A.
Published: June 2003

The current model of the basal ganglia (BG) assumes that neurons use a firing rate renewal code for movement computing under normal and pathological conditions. Here, we report nonrenewal firing (neuronal firing is influenced by its own previous activity) in cells of the anesthetized rat's substantia nigra (SN). Both compensatory (short interspike intervals (ISIs) are followed by long ISIs and vice versa) and persistent (short and long ISIs cluster for long time periods) nonrenewal activity was found in 52.6% and 33.8% of SN cells, respectively. A compensatory pattern was found in 77.7% of DA cells, but in only 9.8% of GABA‐cells. Conversely, a persistent pattern was observed in 74.6% of GABAergic cells and in only 9.9% of DA cells. These findings indicate two types of nonrenewal firing pattern codes specifically present in SN dopaminergic and GABAergic neurons. Disruption of these patterns may play a role in the pathophysiology of basal ganglia disorders such as Parkinson's disease and dyskinesias. Synapse 49:216–225, 2003. © 2003 Wiley‐Liss, Inc.
Dual effects of intermittent or continuous L‐DOPA administration on gene expression in the globus pallidus and subthalamic nucleus of adult rats with a unilateral 6‐OHDA lesion
Authors: Nielsen Kirsten M. , Soghomonian Jean‐Jacques
Published: June 2003

Intermittent oral doses of levodopa (L‐DOPA) are routinely used to treat Parkinson's disease, but with prolonged use can result in adverse motor complications, such as dyskinesia. Continuous administration of L‐DOPA achieves therapeutic efficacy without producing this effect, yet the molecular mechanisms are unclear. This study examined, by in situ hybridization histochemistry, the effects of continuous or intermittent L‐DOPA administration on gene expression in the globus pallidus and subthalamic nucleus of adult rats with a unilateral 6‐hydroxydopamine (6‐OHDA) lesion of the nigrostriatal pathway. Results were compared to 6‐OHDA‐treated rats receiving vehicle. Our results provide original evidence that continuous L‐DOPA normalizes the 6‐OHDA‐lesion‐induced increase in mRNA levels encoding for the 67 kDa isoform of glutamate decarboxylase in neurons of the globus pallidus and cytochrome oxidase subunit I mRNA levels in the subthalamic nucleus. The extent of normalization did not differ between the continuous and intermittent groups. In addition, intermittent L‐DOPA induced an increase in the mRNA levels encoding for the 65 kDa isoform of glutamate decarboxylase in globus pallidus neurons ipsilateral to the lesion and a bilateral increase in c‐fos mRNA expression in the subthalamic nucleus. These results suggest that continuous L‐DOPA tends to normalize the 6‐OHDA‐lesion‐induced alterations in cell signaling in the pallido‐subthalamic loop. On the other hand, we propose that chronic intermittent L‐DOPA exerts a dual effect by normalizing cell signaling in a subpopulation of neurons in the globus pallidus and subthalamic nucleus while inducing abnormal signaling in another subpopulation. Synapse 49:246–260, 2003. © 2003 Wiley‐Liss, Inc.
Displacement of the PET ligand 18F‐MPPF by the electrically evoked serotonin release in the rat hippocampus
Authors: Rbah Latifa , Leviel Vincent , Zimmer Luc
Published: June 2003

The effects of the electrically evoked serotonin release were evaluated on the binding of 18F‐MPPF in the hippocampus of anesthetized rats. The specific binding of 18F‐MPPF was measured by an implanted β‐microprobe and the serotonin (5‐HT) extracellular concentration was measured by microdialysis under the same conditions. Our results showed that the 10‐, 20‐, or 30‐min electrical stimulation of the raphe nucleus elicited a significant increase in extracellular 5‐HT, only detectable in the presence of a 5‐HT reuptake inhibitor in the perfusate (5 μM clomipramine). Interestingly, the raphe stimulations were associated with a 27–76% reversible decrease of the 18F‐MPPF specific binding in the hippocampus, but an unchanged extracellular 18F‐MPPF collected in dialysates. Considered together, these observations suggest that 18F‐MPPF binding is sensitive to 5‐HT released at a neuronal level. This compartment, explored by the β‐microprobe, is probably distinct from the extracellular compartment, explored by microdialysis. Synapse 49:239–245, 2003. © 2003 Wiley‐Liss, Inc.
Anticataleptic activity of cathinone and MDMA (Ecstasy) upon acute and subchronic administration in rat
Authors: Banjaw Mehret Yerdaw , Mayerhofer Andreas , Schmidt Werner J.
Published: June 2003

It was recently demonstrated that acute administration of 3,4‐methylenedioxymethamphet‐amine (MDMA, “Ecstasy”) is capable of counteracting haloperidol‐induced catalepsy in rats. The present study was done with another psychostimulant, S‐(−)‐cathinone. In these experiments, 32 male Sprague‐Dawley rats, 225 ± 25 g, were used. They were divided into three groups. All groups received 0.5 mg/kg haloperidol in normal saline (s.c.) as a first injection. Then 30 min later each group received either isotonic phosphate‐buffered saline, 1 mg/kg S‐(−)‐cathinone, or 2.5 mg/kg (RS)‐MDMA (s.c.) as a second injection. The results of descent latency on both the horizontal bar and vertical grid showed that S‐(−)‐cathinone or (RS)‐MDMA upon acute administration induces a strong anticataleptic activity (P < 0.0001) compared to rats treated with haloperidol plus vehicle. The effect of both drugs was later masked upon subchronic administration (days 2–7, 26–29). This is probably due to sensitization of cataleptic behavior. However, when the same groups of rats were tested on day 8 in a different task, i.e., open‐field, they showed a significant difference (P < 0.05). The detailed mechanism of the observed strong anticataleptic activity of S‐(−)‐cathinone (which is considered a potent dopamine releaser) requires further investigation. Synapse 49:232–238, 2003. © 2003 Wiley‐Liss, Inc.
Effects of an adenosine A2A receptor blockade in the nucleus accumbens on locomotion, feeding, and prepulse inhibition in rats
Authors: Nagel Jens , Schladebach Henning , Koch Michael , Schwienbacher Isabel , Müller Christa E. , Hauber Wolfgang
Published: June 2003

The nucleus accumbens (NAc) subserves behaviors governed by natural rewards, i.e., feeding or exploration, and has been implicated in control of prepulse inhibition (PPI), a measure of sensorimotor gating. The present study sought to determine whether a tonic stimulation of adenosine A2A receptors in the rat NAc is involved in control of spontaneous locomotor activity, feeding behavior, and PPI. To this end, bilateral microinfusions of a prodrug (MSX‐3) (3 μg and 5 μg in 1 μl per side) of the selective A2A receptor antagonist MSX‐2 or vehicle (1 μl per side) were administered into the NAc. Results show that blockade of intra‐NAc adenosine A2A receptors by a high (5 μg), but not by a low (3 μg), dose of MSX‐3 increased locomotor activity in an open field, reduced food intake, and delayed intake onset in food‐deprived rats examined in a test cage with standard laboratory chow. Furthermore, PPI was significantly disrupted after intra‐NAc infusion of 5 μg, but not 3 μg, MSX‐3. These findings suggest that locomotor activity as well as intact PPI and feeding behavior rely on tonic activation of intra‐NAc A2A receptors. The data add further support to the view that adenosine is a tonically active modulator of striatal function through actions on A2A receptors. Synapse 49:279–286, 2003. © 2003 Wiley‐Liss, Inc.
An 8‐day extensive elemental, but not contextual, fear conditioning potentiates hippocampal‐lateral septal synaptic efficacy in mice
Authors: Desmedt Aline , Garcia René , Jaffard Robert
Published: June 2003

Previous findings have suggested a critical role for hippocampal‐lateral septal (HPC‐LS) synaptic transmission in the modulation of elemental vs. contextual fear conditioning. Pharmacologically‐ or electrophysiologically‐induced increases in HPC‐LS neurotransmission were shown to be associated with both an increase in elemental and a decrease in contextual fear conditioning. However, elemental conditioning, induced by an unconditional stimulus (US) that was explicitly paired with a simple conditional stimulus (CS), did not result in any change in this neurotransmission when two tone CS‐footshock US pairings were provided. The present experiment was thus designed to investigate directly, in mice, whether extensive elemental conditioning (repeated CS‐US pairings) could induce an increase in HPC‐LS neurotransmission. For that purpose, over 8 days, an elemental conditioning group was repeatedly submitted to CS‐US pairings in either one context (A) or another (B) depending on the training day. Hence, whichever the context, the tone CS was the relevant predictive stimulus for the occurrence of the footshock US. In contrast, a contextual conditioning group was submitted to the same regimen except that the US was delivered only in context A and was never paired with the CS, making, thereby, the context A the relevant predictor for the US regardless of the occurrence of the tone CS. Results show that during re‐exposure of the animals to either context A or B, a significant increase in HPC‐LS neurotransmission was selectively associated with the repeated elemental conditioning. This study supports the idea that changes in HPC‐LS neurotransmission may modulate the strength of simple CS‐US associations, and suggests that alterations of hippocampal functioning might be involved. Synapse 49:270–278, 2003. © 2003 Wiley‐Liss, Inc.
An automated pottery archival and reconstruction system
Authors: Kampel Martin , Sablatnig Robert
Published: June 2003

Motivated by the current requirements of archaeologists, we are developing an automated archival system for archaeological classification and reconstruction of ceramics. Our system uses the profile of an archaeological fragment, which is the cross‐section of the fragment in the direction of the rotational axis of symmetry, to classify and reconstruct it virtually. Ceramic fragments are recorded automatically by a 3D measurement system based on structured (coded) light. The input data for the estimation of the profile is a set of points produced by the acquisition system. By registering the front and the back views of the fragment the profile is computed and measurements like diameter, area percentage of the complete vessel, height and width are derived automatically. We demonstrate the method and give results on synthetic and real data. Copyright © 2003 John Wiley & Sons, Ltd.
NRC 3D imaging technology for museum and heritage applications
Authors: Taylor J. , Beraldin J.‐A. , Godin G. , Cournoyer L. , Baribeau R. , Blais F. , Rioux M. , Domey J.
Published: June 2003

The National Research Council of Canada (NRC) has developed and patented three high‐resolution 3D imaging systems and processing algorithms which have been applied to a wide range of museum and heritage recording applications. The systems have been designed for different imaging applications and, in collaboration with a number of national and international museums and cultural agencies, have been used to scan a wide variety of objects and sites. The objective of this paper is to present a summary of the 3D technology and examples of its heritage applications. Copyright © 2003 John Wiley & Sons, Ltd.
Reconstruction of dynamic 3D scene based on visual hull and view morphing
Authors: Yang Hyun S. , Han Taewoo , Lee Juho
Published: June 2003

In this paper, we propose a new method that processes multiple synchronized video sequences and generates 3D rendering of dynamic objects in the video. It exploits an efficient image‐based reconstruction scheme that constructs and shades 3D models of objects from silhouette images by combining image‐based visual hull and view morphing. The proposed hybrid method improves the speed and the quality of the previous visual hull sampling methods. We designed and implemented a system based on this method which is relatively low cost and does not require any special hardware or specific environment. Copyright © 2003 John Wiley & Sons, Ltd.
ArtShop: an art‐oriented image‐processing tool for cultural heritage applications
Authors: Cappellini V. , Barni M. , Corsini M. , De Rosa A. , Piva A.
Published: June 2003

Advances in electronic imaging over recent years have encouraged the development of new tools for cultural heritage applications. In this paper a software application called ArtShop is described, containing some tools for artwork image restoration, developed during several years of research at the Image and Communications Laboratory of the University of Florence. Copyright © 2003 John Wiley & Sons, Ltd.
Truth and credibility as a double ambition: reconstruction of the built past, experiences and dilemmas
Authors: Bakker Geeske , Meulenberg Frans , Rode Jan de
Published: June 2003

The reconstruction of our historical heritage involves a few fundamental problems. We mention only two. There can be many interpretations of scientific data which can result in different reconstructions: however, the appearance of an image or animation in a digital format out of context is nearly always misleading. Therefore, the verisimilitude of the computer‐based image should be questioned in the same manner as a picture in a journal, but the digital medium seldom facilitates this questioning. Furthermore, the diffusion of visualizations raises concerns; currently there is no established ontology to moderate the process. This article is based on our own experiences and attempts to contribute to this ontology. In this, scientific ‘truth’ will go hand in hand with artistic credibility, which to many may come as a surprise. Copyright © 2003 John Wiley & Sons, Ltd.
State‐dependent prey type preferences of a kleptoparasitic spider Argyrodes flavescens (Araneae: Theridiidae)
Authors: Hui Koh Teck , Li Daiqin
Published: June 2003

Spiders from the theridiid genus Argyrodes exhibit considerable variation in foraging tactics. However, little is known about the conditions under which Argyrodes spiders switch foraging tactics. Argyrodes flavescens (Pickard‐Cambridge) is commonly found in the webs of another spider Nephila pilipes (Fabricius) in Singapore. In this study, a series of prey‐choice tests were conducted for A. flavescens, both in the presence and absence of N. pilipes, to investigate the state‐dependent prey type preference of A. flavescens. It was found that, in the absence of N. pilipes, well‐fed A. flavescens took houseflies more than fruit flies, but starved A. flavescens took more fruit flies than houseflies. Whether N. pilipes spiders were present or absent, both well‐fed and starved A. flavescens preferred living prey and rarely took wrapped prey of any kind. When well fed, A. flavescens rarely took mealworms. However, when starved, A. flavescens tended to take freshly captured prey, and also tended to feed together with N. pilipes on a housefly or mealworm captured by N. pilipes. Whether A. flavescens were absent or present, both well‐fed and starved N. pilipes took mealworm larvae more often than they took houseflies, and they never attacked fruit flies. This is the first study to show that Argyrodes spiders alter their foraging tactics depending on hunger level, prey type, or the presence of the host. In doing so, Argyrodes spiders may maximize their energy gain and minimize predation risk in different circumstances.
Thermoregulation and roost selection by reproductive female big brown bats (Eptesicus fuscus) roosting in rock crevices
Authors: Lausen Cori L. , Barclay Robert M. R.
Published: June 2003

A free‐ranging maternity colony of big brown bats Eptesicus fuscus roosting in rock crevices along the South Saskatchewan River in south‐eastern Alberta, Canada, was studied to understand better the discrepancy that exists in the literature regarding torpor use by reproductive female bats. Using radio‐telemetry, thermoregulatory patterns and roost microclimate were recorded for pregnant, lactating and post‐lactating females. Relative torpor use is described in several ways: the proportion of days on which torpor was used, depth, minimum body temperature, time spent in torpor, and a comprehensive torpor unit (degree‐min). Pregnant and lactating female E. fuscus used torpor to the same extent overall (degree‐min), but pregnant bats used torpor less frequently and with more time in deep torpor. Torpor was used to the greatest extent after weaning (post‐lactation). Evidence is presented that the cost:benefit ratio for deep and prolonged periods of torpor may be highest during lactation. Microclimates of rock‐crevice roosts mirrored the use of torpor throughout reproduction by bats. Lactation roosts (deeper, larger opening size) were more thermally stable and remained warmer at night compared to the shallow roosts used by pregnant and post‐lactating females. It is shown that conclusions about relative use of torpor can differ depending on the units of comparison, necessitating measurement of all aspects of torpor (depth, duration and frequency). Comprehensive measurements, individual‐based normothermic temperatures, and a definition of torpor that accounts for all energy savings, allow a more accurate depiction of patterns and facilitates inter‐study comparisons.
Foraging in the subterranean social highveld mole‐rat (Cryptomys hottentotus pretoriae): an investigation into mass‐dependent geophyte use and foraging patterns
Authors: Malherbe G. P. , Bennett N. C. , Schoeman A. S.
Published: June 2003

The foraging behaviour of captive colonies of the highveld mole‐rat Cryptomys hottentotus pretoriae was investigated in an artificial soil‐filled burrow system provided with four trays (patches) that varied in geophyte density and mass. An initial trial involving empty trays (only soil) revealed that there was no preference for any specific tray. There were no statistically significant preferences for excavating in any of the patches of different geophyte density. No preferences were evident for excavation in patches containing geophytes of different mass classes. Empty patches seemed to be preferred over patches containing geophytes when combinations of geophyte density/mass were investigated. The duration of handling and the rate of consumption of geophytes were recorded for 23 individuals of two mass classes. Handling time of geophytes was not related to mole‐rat sex, but was strongly linked to mole‐rat mass class. Handling time of geophytes was related to geophyte mass class. Small geophytes were less profitable to consume. These findings are considered in light of optimal foraging theory and the situation in the field. It was concluded that the mole‐rats generally followed the qualitative predictions of optimal foraging theory, although falling short of being energy maximizers.
A composite species‐level phylogeny of the ‘Insectivora’ (Mammalia: Order Lipotyphla Haeckel, 1866)
Authors: Grenyer Richard , Purvis Andy
Published: June 2003

The first MRP (matrix representation with parsimony) supertree phylogeny of the Lipotyphla is presented, covering all the families that were considered to make up the traditional mammalian order Insectivora. The phylogeny does not examine relationships within the shrew subfamily Crocidurinae, but all other taxa are considered at the species level, drawing upon 41 years of systematic literature and combining information from 47 published sources. The MRP technique is also critically discussed. This study will be of use to comparative biology studies of the Lipotyphla (or of mammals as a whole) and is a rigorous review of past systematic work, as well as clearly demonstrating our current level of knowledge. The supertree clearly details a strong imbalance in phylogenetic understanding across the taxon: a great deal is known about the hedgehogs and gymnures (Erinaceidae), the New World moles (Talpidae), Palaearctic species of Sorex (subgenus Sorex) and the relationships between genera of red‐toothed shrews (Soricinae). The supertree, however, clearly shows areas where our knowledge is conflicting or non‐existent, and these gaps do not always correspond to obscure species: nothing is known about the systematics of Old World mole genera. Also very little is known about golden moles (Chrysochloridae) and the shrew‐tenrec genus Microgale, some of the most threatened mammals on Earth.
Duetting in insects – does call length influence reply latency?
Authors: Bailey W. J. , Hammond T. J.
Published: June 2003

A meta‐analysis of the duetting patterns of insect taxa that signal by bioluminescence, substrate vibration, or sound was used to test the prediction that call length by the initiating male influences the latency of reply of the female. There was a significant and positive relationship between these two measures. Although tests on the entire dataset did not consider phylogeny, when all members of one sub‐family of bushcricket, the Phaneropterinae, were isolated there was a significant and positive relationship between call length and reply latency. Two explanations are suggested. First, the female must wait for the conclusion of a long and potentially variable message; there is uncertainty as to when the call has finished before she can reply. Second, is the requirement of the female to process information; a longer male call, with more information requires more processing than a brief call. The authors suggest that long reply latencies may be vulnerable to intrusion by competing mates. One defensive tactic of potential female partners is to insert a trigger pulse that indicates to the female when the long and complex call has concluded. This behaviour may be considered as acoustic mate guarding and one example is given of this behaviour.
Does the handedness of the pebble crab Eriphia smithii influence its attack success on two dextral snail species?
Authors: Shigemiya Yusuke
Published: June 2003

The predaceous crab Eriphia smithii (Xanthidae) has one larger claw with molar teeth on either the right or the left cheliped, which it uses to crush the shell of prey. Whether the handedness of crabs affected successful predation on two snail species, Nerita albicilla (Neritidae) and Planaxis sulcatus (Planaxidae) was experimentally investigated. The fate of snails of each species was analysed by multiple logistic regression with three explanatory variables: handedness, shell‐size index and individuality of crabs. No effect of handedness was detected in attacks on N. albicilla, probably as a result of the spherical and more symmetrical shell morphology of this species. In contrast, right‐handedness contributed to greater attack success on P. sulcatus, which has more conical shells. Further investigation of how snail shells were broken revealed that left‐handed crabs had more difficulty breaking the aperture of larger P. sulcatus, which was thought to cause the difference in attack success between right‐ and left‐handed crabs. The advantages conferred by handedness are discussed.
Apomorphic and plesiomorphic ITS‐1 rDNA patterns in morphologically similar snails (Stylommatophora: Vallonia), with estimates of divergence time
Authors: Korte Anja , Armbruster Georg F. J.
Published: June 2003

Morphological classification of snail shells is sometimes arbitrary and misleading in correct species delimitation. This topic is investigated in four nominal species of the minute gastropods of the genus Vallonia (V. pulchella, V. excentrica, V. costata and V. enniensis). First, individuals are classified according to their shell morphology. Second, variation in ribosomal internal transcribed spacer 1 DNA (ITS‐1 rDNA) is analysed. Using a cladistic approach, the nucleotide positions of the ITS‐1 are elucidated on apomorphic and plesiomorphic character states (outgroup=Acanthinula aculeata; Valloniidae). The molecular data yield evidence that the morphospecies V. excentrica is a paraphyletic group, comprising just a loose arrangement of individuals with similar shells. Data on fossil shells and putative divergence time are also elucidated. In the monograph on Vallonia it has been suggested that the split between the branch of V. costata and the branch of V. pulchella, V. excentrica and V. enniensis could have been in the upper Cretaceous. Based on the ITS‐1 sequence alignment and the number of variable nucleotide positions, it is suggested that the last common ancestor of both branches lived at some time during the Miocene or even the Pliocene. Therefore, the fossil stem lines of Vallonia should be newly interpreted.
Prey abundance and prey selection by tigers (Panthera tigris) in a semi‐arid, dry deciduous forest in western India
Authors: Bagchi S. , Goyal S. P. , Sankar K.
Published: June 2003

Food habits of tigers Panthera tigris in terms of prey abundance were studied in the semi‐arid deciduous forests of Ranthambhore National Park, western India, between November 2000 and April 2001. Wild prey availability was assessed by line transects (n=8) and prey selection by the tigers was determined from analysis of scats (n=109). Compared to some other parts of the country, prey abundance was found to be high at 96.65 animals km−2. Chital Axis axis was the most abundant wild prey in the study area, followed by common langur Presbytis entellus, sambar Cervus unicolor, nilgai Boselaphus tragocamelus, wild pig Sus scrofa and chinkara Gazella bennetti. Chital (c. 31%) and sambar (c. 47%) constituted the bulk of the tigers' diet and were preferred prey. Nilgai and chinkara contributed minimally to the tigers' diet (c. 5–7% and <1%, respectively) and were used less than their availability. Domestic livestock made up 10–12% of the tigers' diet. The average weight of an animal consumed was between 107 and 114 kg reflecting a preference for large prey. The analysis reveals that parts of Ranthambhore have high prey abundance, thus making it important for long‐term tiger conservation. Despite the high prey abundance, tigers were still considerably dependent on domestic livestock, posing challenges for the park management to resolve potential areas of conflict.
Redescription of Fridericia heliota (Annelida, Clitellata: Enchytraeidae), a luminous worm from the Siberian taiga, with a review of bioluminescence in the Oligochaeta
Authors: Rota Emilia , Zalesskaja Nadezhda T. , Rodionova Natalja S. , Petushkov Valentin N.
Published: June 2003

The Siberian enchytraeid Fridericia heliota Zalesskaja, 1990 has so far been known only through a paper in Russian briefly describing its luminescence and the major external and internal morphological features. The present study expands that preliminary description, amending it as regards the chaetal formula, the clitellar pattern, the form of the nephridia and the occurrence of glands at the spermathecal orifices, and providing a more comprehensive taxonomic characterization of the species. More detailed information is also given on its habitat and geographical range as well as on its unusual luminous properties. In F. heliota, the production of light is confined to the body wall with a pattern corresponding to that of the epidermal gland cells, although it does not involve discharge of luminous mucus. This contrasts with observations on other enchytraeids and on the oligochaetes in general. Records of luminosity in the Oligochaeta are reviewed with comments.