bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Rpi‐blb2 gene from Solanum bulbocastanum is an Mi‐1 gene homolog conferring broad‐spectrum late blight resistance in potato
Authors: van der Vossen Edwin A.G. , Gros Jack , Sikkema Anne , Muskens Marielle , Wouters Doret , Wolters Petra , Pereira Andy , Allefs Sjefke 
Published: September 2005

SummaryThe necessity to develop potato and tomato crops that possess durable resistance against the oomycete pathogen Phytophthora infestans is increasing as more virulent, crop‐specialized and pesticide resistant strains of the pathogen are rapidly emerging. Here, we describe the positional cloning of the Solanum bulbocastanum‐derived Rpi‐blb2 gene, which even when present in a potato background confers broad‐spectrum late blight resistance. The Rpi‐blb2 locus was initially mapped in several tetraploid backcross populations, derived from highly resistant complex interspecific hybrids designated ABPT (an acronym of the four Solanum species involved:S. acaule, S. bulbocastanum, S. phureja and S. tuberosum), to the same region on chromosome 6 as the Mi‐1 gene from tomato, which confers resistance to nematodes, aphids and white flies. Due to suppression of recombination in the tetraploid material, fine mapping was carried out in a diploid intraspecific S. bulbocastanum F1 population. Bacterial artificial chromosome (BAC) libraries, generated from a diploid ABPT‐derived clone and from the resistant S. bulbocastanum parent clone, were screened with markers linked to resistance in order to generate a physical map of the Rpi‐blb2 locus. Molecular analyses of both ABPT‐ and S. bulbocastanum–derived BAC clones spanning the Rpi‐blb2 locus showed it to harbor at least 15 Mi‐1 gene homologs (MiGHs). Of these, five were genetically determined to be candidates for Rpi‐blb2. Complementation analyses showed that one ABPT‐ and one S. bulbocastanum‐derived MiGH were able to complement the susceptible phenotype in both S. tuberosum and tomato. Sequence analyses of both genes showed them to be identical. The Rpi‐blb2 protein shares 82% sequence identity to the Mi‐1 protein. Significant expansion of the Rpi‐blb2 locus compared to the Mi‐1 locus indicates that intrachromosomal recombination or unequal crossing over has played an important role in the evolution of the Rpi‐blb2 locus. The contrasting evolutionary dynamics of the Rpi‐blb2/Mi‐1 loci in the two related genomes may reflect the opposite evolutionary potentials of the interacting pathogens.
Optimization of biometry for intraocular lens implantation using the Zeiss IOLMaster
Authors: Madge Simon N. , Khong C. H. , Lamont Meon , Bansal Atul , Antcliff Richard J. 
Published: September 2005

Abstract.Purpose:  To compare the accuracy of biometry using conventional A‐scan ultrasonography and partial coherence interferometry, and to improve the accuracy of biometry by sequential audit of postoperative refractive error. Methods:  The study was performed in three phases. In phase 1, 20 consecutive patients undergoing routine phacoemulsification underwent biometry using both A‐scan ultrasonography and the Zeiss IOLMaster (ZIOLM). A single experienced optometrist refracted all patients 2 weeks after surgery. The errors between expected and achieved refraction were calculated and compared between the two methods. In phases 2 and 3, a further 22 and 20 patients, respectively, were recruited and only the ZIOLM was used for biometry. The manufacturer's suggested A‐constant was refined and the error between expected and achieved refraction was calculated. Results:  In phase 1, the median unexpected error for the ZIOLM was +0.63 (interquartile range +0.368 to +1.015) and for A‐scan biometry was − 0.24 (interquartile range − 1.335 to +0.802). In phase 1 65% of patients' postoperative refractions were found to be within 1.0 D of emmetropia using the ZIOLM (55% using A‐scan biometry). Refinements to the A‐constant improved this to 95% by phase 3. Conclusion:  An error was identified in IOL power estimation with the ZIOLM, when using the manufacturer's recommended A‐constant (recommended and previously optimized ultrasound A‐constant 118.0; ZIOLM optimized A‐constant 118.6). Serial modifications to the A‐constant were successful in reducing the unexpected error to well within the tolerance limits of published international standards.
Contrasting genetic structures across two hybrid zones of a tropical reef fish, Acanthochromis polyacanthus (Bleeker 1855)
Authors: Van Herwerden L. , Doherty P. J. 
Published: September 2005

Abstract
Hybrid zones are natural laboratories offering insights into speciation processes. Narrow hybrid zones are less common in the sea than on land consistent with higher dispersal among marine populations. Acanthochromis polyacanthus is an unusual bony marine fish with philopatric dispersal that exists as allopatric stocks of white, bicoloured and black fish on the Great Barrier Reef (GBR). At two latitudes, different morphs coexist and hybridize at narrow contact zones. Sequence data from mitochondrial Hypervariable Region 1 revealed contrasting patterns of introgression across these zones. At the northern hybrid zone, a single clade of mitochondrial haplotypes was found in all white fish, hybrids and tens of kilometres into pure bicoloured stock. At the southern hybrid zone, there was no introgression of mitochondrial genes into black fish and hybrids shared the bicoloured haplotypes. Based on this asymmetry, we postulate that black fish from the southern GBR have experienced a selective sweep of their mitochondrial genome, which has resulted in almost total reproductive isolation.
Stable genetic polymorphism in heterogeneous environments: balance between asymmetrical dispersal and selection in the acorn barnacle
Authors: Véliz D. , Duchesne P. , Bourget E. , Bernatchez L. 
Published: September 2005

Abstract
Elucidating the processes responsible for maintaining polymorphism at ecologically relevant genes is intimately related to understanding the interplay between selection imposed by habitat heterogeneity and a species’ capacity for dispersal in the face of environmental constraints. In this paper, we used a model-based approach to solve equilibria of balanced polymorphism, given values of fitness and larval dispersal among different habitats in the acorn barnacle Semibalanus balanoides from the Gulf of St Lawrence. Our results showed that allele frequencies observed at both MPI* and GPI* loci represented stable equilibria, given empirical estimates of fitness values, and that considerably more larvae dispersed from one region (north) to the other (south) than vice versa. Dispersal conditions were predicted to be similar for the maintenance of polymorphism at both loci. Moreover, the values of asymmetrical dispersal required by the model to reach stable equilibria were compatible with empirical estimates of larval dispersal and oceanic circulation documented in this system. Overall, this study illustrated the usefulness of a modified and computable version of Bulmer's model (1972) in order to test hypotheses of balanced polymorphism resulting from interactions between spatial selection and asymmetrical dispersal.
Correlations between heterozygosity and measures of genetic similarity: implications for understanding mate choice
Authors: Roberts S. C. , Hale M. L. , Petrie M. 
Published: September 2005

Abstract
There is currently considerable interest in testing the effects of genetic compatibility and heterozygosity on animal mate preferences. Evidence for either effect is rapidly accumulating, although results are not always clear-cut. However, correlations between mating preferences and either genetic similarity or heterozygosity are usually tested independently, and the possibility that similarity and heterozygosity may be confounded has rarely been taken into account. Here we show that measures of genetic similarity (allele sharing, relatedness) may be correlated with heterozygosity, using data from 441 human individuals genotyped at major loci in the major histocompatibility complex, and 281 peafowl (Pavo cristatus) individuals genotyped at 13 microsatellite loci. We show that average levels of allele sharing and relatedness are each significantly associated with heterozygosity in both humans and peafowl, that these relationships are influenced by the level of polymorphism, and that these similarity measures may correlate with heterozygosity in qualitatively different ways. We discuss the implications of these inter-relationships for interpretation of mate choice studies. It has recently become apparent that mating preferences for ‘good genes’ and ‘compatible genes’ may introduce discordant choice amongst individuals, since the optimal mate for one trait may not be optimal for the other, and our results are consistent with this idea. The inter-relationship between these measures of genetic quality also carries implications for the way in which mate choice studies are designed and interpreted, and generates predictions that can be tested in future research.
An experimental test of the causes of small-scale phenotypic differentiation in a population of great tits
Authors: Shapiro B. J. , Garant D. , Wilkin T. A. , Sheldon B. C. 
Published: September 2005

Abstract
Phenotypic differentiation between populations is thought to occur mainly at spatial scales where gene-flow is restricted and selection regimes differ. However, if gene flow is nonrandom, dispersal may reinforce, rather than counteract, evolutionary differentiation, meaning that differences occurring over small scales might have a genetic basis. The purpose of this study was to determine the cause of differences in mean phenotype between two parts of a population of great tits Parus major, separated by &lt;3 km. We conducted a partial cross-fostering experiment between two contrasting parts of this population to separate genetic and environmental sources of variation, and to test for gene–environment interaction. We found strong environmental effects on nestling size, mass and condition index, with nestlings reared in a low density part of the population being larger, heavier and in better condition, than those in a high density part, irrespective of their origin. In addition, we found smaller, but significant, differences in nestling condition and shape associated with the areas that birds originated from, suggesting the presence of genetic differences between parts of this population. There was no evidence of gene–environment interaction for any character. This experiment is thus consistent with previous analyses suggesting that differences between parts of this population had evolved recently, apparently due to phenotype-dependent dispersal, and indicates that population differentiation can be maintained over small spatial scales despite extensive dispersal.
Does selection by resistant hosts trigger local adaptation in plant–pathogen systems?
Authors: Montarry J. , Corbiere R. , Lesueur S. , Glais I. , Andrivon D. 
Published: September 2005

Abstract
Understanding the consequences of selection by host resistance on pathogen population structure provides useful insights into the dynamics of host–parasite co-evolution processes and is crucial for effective disease management through resistant cultivars. We tested general vs. local population adaptation to host cultivars, by characterizing a French collection of Phytophthora infestans (the causal organism of potato late blight) sampled during two consecutive years on cultivars exhibiting various levels of resistance. Local populations were structured by the host for virulence (qualitative pathogenicity) but also for aggressiveness (quantitative pathogenicity). All populations had a low genotypic diversity for amplified fragment length polymorphisms (AFLPs), and presumably consisted of a few closely related clonal lineages. No correlation was detected between pathogenicity traits and AFLP genotypes. The data support the hypothesis of general adaptation for aggressiveness, to which directional selection for virulence is superimposed when race-specific resistance is introduced.
Role of chondroitin sulphate in the uptake of β‐VLDL by brain cells
Authors: Rapp Alfred , Hüttinger Manfred 
Published: September 2005

AbstractProteoglycans (PGs) have been suggested to work as receptors in lipoprotein uptake mechanisms. An interaction between apolipoprotein E (apoE) and glucosaminoglycans (GAG), polysaccharides linked to proteoglycans, has been proposed in this pathway. At the same time, proteoglycans, apoE as well as lipoprotein receptors have been reported to be constituents of amyloid plaques, one hallmark of Alzheimer's disease. With this study, we are the first to investigate the interaction between beta very low density lipoprotein (β‐VLDL) and a neuronal highly abundant GAG, chondroitin sulphate (CS), comparing hippocampal neurons, expressing high levels of low density lipoprotein receptor related protein (LRP) and U373 astrocytoma cells, highly positive for the low density lipoprotein receptor (LDLR). We were able demonstrate that degradation of chondroitin sulphate proteoglycans (CSPGs) with chondroitinase ABC resulted in reduced 125I‐β‐VLDL uptake. We showed that externally added CSs compete with internalization of β‐VLDL. The effect was found to be dose‐dependent, but was influenced neither by cell type, nor receptor type. The position of sulphation of added CSs showed only a slight influence. The data generated suggested an interaction between apolipoproteins and soluble CSs; therefore, 3H‐cholesterol linked to apoE was coadministered with CSs to the cells. The results revealed that apoE bound, but no unbound cholesterol, was reduced in cellular internalization, suggesting that CSPGs may be involved in lipoprotein uptake in the intact brain, mediated, at least in part, by apoE.
Hemispheric asymmetry for spectral and temporal processing in the human antero‐lateral auditory belt cortex
Authors: Schönwiesner Marc , Rübsamen Rudolf , Von Cramon D. Yves 
Published: September 2005

AbstractThe present study investigates the acoustic basis of the hemispheric asymmetry for the processing of speech and music. Experiments on this question ideally involve stimuli that are perceptually unrelated to speech and music, but contain acoustic characteristics of both. Stimuli in previous studies were derived from speech samples or tonal sequences. Here we introduce a new class of noise‐like sound stimuli with no resemblance of speech or music that permit independent parametric variation of spectral and temporal acoustic complexity. Using these stimuli in a functional MRI experiment, we test the hypothesis of a hemispheric asymmetry for the processing of spectral and temporal sound structure by seeking cortical areas in which the blood oxygen level dependent (BOLD) signal covaries with the number of simultaneous spectral components (spectral complexity) or the temporal modulation rate (temporal complexity) of the stimuli. BOLD‐responses from the left and right Heschl's gyrus (HG) and part of the right superior temporal gyrus covaried with the spectral parameter, whereas covariation analysis for the temporal parameter highlighted an area on the left superior temporal gyrus. The portion of superior temporal gyrus in which asymmetrical responses are apparent corresponds to the antero‐lateral auditory belt cortex, which has been implicated with spectral integration in animal studies. Our results support a similar function of the anterior auditory belt in humans. The findings indicate that asymmetrical processing of complex sounds in the cerebral hemispheres does not depend on semantic, but rather on acoustic stimulus characteristics.
Loss of Gli3 enhances the viability of embryonic telencephalic cells in vitro
Authors: Zaki Paulette A. , Martynoga Ben , Delafield‐Butt Jonathan T. , Fotaki Vassiliki , Yu Tian , Price David J. 
Published: September 2005

AbstractThe transcription factor Gli3 is important for brain and limb development. Mice homozygous for a mutation in Gli3 (Gli3Xt/Xt) have severe abnormalities of telencephalic development and previous studies have suggested that aberrant cell death may contribute to the Gli3Xt/Xt phenotype. We demonstrate that telencephalic cells from embryonic Gli3Xt/Xt embryos survive better and are more resistant to death induced by cytosine arabinoside, a nucleoside analogue that induces death in neuronal progenitors and neurons, than are control counterparts in vitro. Culture medium conditioned by Gli3Xt/Xt cells is more effective at enhancing the viability of control telencephalic cells than medium conditioned by control cells, indicating that Gli3Xt/Xt cells release a factor or factors which enhance telencephalic cell viability. Gli3Xt/Xt cells are also more sensitive to released factors present in conditioned media. These data suggest that Gli3 plays both cell‐autonomous and cell‐nonautonomous roles in mediating telencephalic cell viability.
Anatomical evidence for an anticonvulsant relay in the rat ventromedial medulla
Authors: Shehab Safa , McGonigle David , Hughes David I. , Todd Andrew J. , Redgrave Peter 
Published: September 2005

AbstractPharmacological manipulation of the ventrolateral pontine reticular formation (vlPRF) of rats has an anticonvulsant effect in the maximal electroshock model of epilepsy. This study presents three anatomical experiments that determine the efferent projections from this region likely to mediate this anticonvulsant effect. In the first, the anterograde tracer biotinylated dextran amine (BDA) was injected into the vlPRF. A strong projection to the ventromedial medullary reticular formation (vmMRF) was revealed which continued only weakly to the spinal cord. In the second experiment, double‐label procedures were used to indicate whether the BDA‐labelled terminals from the vlPRF make contacts with neurons in vmMRF, retrogradely labelled with cholera‐toxin B subunit from the lumbar spinal cord. Sections of the vmMRF were examined by: (i) light microscopy which showed significant overlap between terminals from vlPRF and retrogradely‐labelled reticulospinal cells; (ii) confocal microscopy which showed labelled terminals in close association with reticulospinal cell bodies; and (iii) electron microscopy which showed vlPRF terminals making synaptic contact with reticulospinal neurons. Finally, immunohistochemical procedures in combination with anterograde tracing revealed that significant numbers of terminals labelled from vlPRF were also positive for markers of glutamatergic or GABAergic neurotransmission. This suggests that the projection from the vlPRF to the vmMRF is likely to include several different functional components. These connections could represent a final critical link of an anticonvulsant circuit that originates in the dorsal midbrain and projects via relays in the vlPRF and the vmMRF to interact with the low‐level motor circuitry in the spinal cord.
Differential expression of the homeobox gene Pitx3 in midbrain dopaminergic neurons
Authors: Korotkova Tatiana M. , Ponomarenko Alexei A. , Haas Helmut L. , Sergeeva Olga A. 
Published: September 2005

AbstractThe transcription factor Pitx3 is expressed selectively in the midbrain and regulates the differentiation and survival of dopaminergic neurons. Lack of this factor results in a degeneration similar to that seen in Parkinson's disease. We have studied the pattern and the level of expression of Pitx3 in dopaminergic neurons of 3‐ to 4‐week‐old Wistar rats. We report Pitx3 expression in almost all dopaminergic substantia nigra (SN) and ventral tegmental area (VTA) neurons. It is coexpressed with the neuroprotective marker calbindin (CB) in a larger population of VTA (43%) than SN (16%) dopaminergic neurons. The level of Pitx3 mRNA, determined by semiquantitative RT‐PCR, is ≈ 6× higher in VTA than in SN single neurons. In the VTA but not in SN the level of Pitx3 is associated with the presence of CB: in CB‐positive neurons the expression of Pitx3 mRNA is 3.6× higher than in CB‐negative cells. CB is expressed in a larger population of VTA than SN neurons and the relative level of CB expression is 4× higher in VTA than in SN. A higher Pitx3 expression level and higher coexpression of Pitx3 and CB in VTA than in SN neurons may contribute to the different vulnerability of these dopaminergic nuclei to neurodegeneration.
Laminar differences in field potential morphology and long‐term potentiation in motor cortex coronal slices from both unstimulated and previously potentiated rats
Authors: Ji Zhanxin , Boyd Tiffany E. , Froc David J. , Racine Ronald J. 
Published: September 2005

AbstractWe have reported that long‐term potentiation (LTP) can be reliably induced in motor cortex of adult, freely moving rats by the application of spaced and repeated high frequency stimulating trains to the white matter. In the present study, we monitored field potentials (FPs) and LTP in both layer II/III and V in coronal slices of motor cortex taken from implanted control and previously potentiated Long–Evans rats. The baseline FP amplitudes were decreased in layer II/III, and the amplitude of small spikes was significantly increased in layer V in slices from previously potentiated rats compared to unpotentiated control rats. In response to high frequency stimulation applied to the slice itself, both implanted control and previously potentiated rats showed similar levels of LTP in layer II/III. LTP could not be induced in layer V. These results show that layer II/III and V respond differently to high frequency stimulation in vitro. In addition, layer II/III responds very differently in slice compared to chronic preparations.
Specific expression of olfactory binding protein in the aerial olfactory cavity of adult and developing Xenopus
Authors: Millery Julie , Briand Loïc , Bézirard Valérie , Blon Florence , Fenech Claire , Richard‐Parpaillon Laurent , Quennedey Brigitte , Pernollet Jean‐Claude , Gascuel Jean 
Published: September 2005

AbstractOlfactory binding proteins (OBP), commonly associated with aerial olfaction, are found in the olfactory mucus of mammals but have never been identified in fish. It is still not clear whether the presence of OBP in aerial olfactory systems is due to phylogenetic or to functional differences linked to the adaptation of the olfactory system to an aerial environment. To test this alternative, the olfactory system of Xenopus offers a unique opportunity because it includes two olfactory cavities, one of which is thought to be devoted to aquatic olfaction and the other to aerial olfaction. We therefore purified and cloned OBPs in two Xenopus species. Xenopus laevis OBP (XlaeOBP) and Xenopus tropicalis OBP (XtroOBP) exhibit 158 and 160 amino acids, respectively, sharing 89 residues. cRNA probes allowed us to demonstrate that XlaeOBP and XtroOBP are expressed at the level of Bowman's gland specifically in the aerial olfactory cavity, as confirmed using anti‐XlaeOBP antiserum. OBP mRNA transcription occurs early during metamorphosis, as early as stage 57. This is the first study to demonstrate that OBPs are exclusively present in the aerial chamber and are only expressed as the tadpole becomes an adult in species which possess both aquatic and aerial olfactory organs.