No evidence for MHC class II-based non-random mating at the gametic haplotype in Atlantic salmon.

Genes of the major histocompatibility complex (MHC) are a likely target of mate choice because of their role in inbreeding avoidance and potential benefits for offspring immunocompetence. Evidence for female choice for complementary MHC alleles among competing males exists both for the pre- and the postmating stages. However, it remains unclear whether the latter may involve non-random fusion of gametes depending on gametic haplotypes resulting in transmission ratio distortion or non-random sequence divergence among fused gametes. We tested whether non-random gametic fusion of MHC-II haplotypes occurs in Atlantic salmon Salmo salar. We performed in vitro fertilizations that excluded interindividual sperm competition using a split family design with large clutch sample sizes to test for a possible role of the gametic haplotype in mate choice. We sequenced two MHC-II loci in 50 embryos per clutch to assess allelic frequencies and sequence divergence. We found no evidence for transmission ratio distortion at two linked MHC-II loci, nor for non-random gamete fusion with respect to MHC-II alleles. Our findings suggest that the gametic MHC-II haplotypes play no role in gamete association in Atlantic salmon and that earlier findings of MHC-based mate choice most likely reflect choice among diploid genotypes. We discuss possible explanations for these findings and how they differ from findings in mammals.

Local adaptation and matching habitat choice in female barn owls with respect to melanic coloration.

Local adaptation is a major mechanism underlying the maintenance of phenotypic variation in spatially heterogeneous environments. In the barn owl (Tyto alba), dark and pale reddish-pheomelanic individuals are adapted to conditions prevailing in northern and southern Europe, respectively. Using a long-term dataset from Central Europe, we report results consistent with the hypothesis that the different pheomelanic phenotypes are adapted to specific local conditions in females, but not in males. Compared to whitish females, reddish females bred in sites surrounded by more arable fields and less forests. Colour-dependent habitat choice was apparently beneficial. First, whitish females produced more fledglings when breeding in wooded areas, whereas reddish females when breeding in sites with more arable fields. Second, cross-fostering experiments showed that female nestlings grew wings more rapidly when both their foster and biological mothers were of similar colour. The latter result suggests that mothers should particularly produce daughters in environments that best match their own coloration. Accordingly, whiter females produced fewer daughters in territories with more arable fields. In conclusion, females displaying alternative melanic phenotypes bred in habitats providing them with the highest fitness benefits. Although small in magnitude, matching habitat selection and local adaptation may help maintain variation in pheomelanin coloration in the barn owl.

Spatial variation in the temporal change of male and female melanic ornamentation in the barn owl.

Because the magnitude of selection can vary between sexes and in space and time, sexually antagonistic selection is difficult to demonstrate. In a Swiss population of barn owls (Tyto alba), a heritable eumelanic colour trait (size of black spots on ventral feathers) was positively selected with respect to yearling survival only in females. It remains unclear whether the absence of negative selection in males is typical in this species. To tackle this issue indirectly, we measured the size of black spots in 1733 skin specimens collected by museums from 1816 to 2001 in seven European countries and in the Middle-East. The temporal change in spot size was sex- and country-specific. In males, spots became smaller particularly in three countries (Middle-East, Italy and Switzerland). In females, the size of spots increased significantly in two countries (UK and Spain) and decreased in two others (Germany and Switzerland). Because migration and phenotypic plasticity cannot explain these results, selection is the most likely cause. The weaker temporal change in spot size in females than males may be because of the combined effect of strong genetic correlation between the sexes and stronger negative selection in males than positive selection in females. We thus suggest that in the barn owl, spot size (or genetically correlated traits) is sexually antagonistically selected and that its pattern of selection may account for the maintenance of its variation and sexual dimorphism.

Performance Evaluation of Docking Programs- Glide, GOLD, AutoDock & SurflexDock, Using Free Energy Perturbation Reference Data: A Case Study of Fructose-1, 6-bisphosphatase-AMP Analogs.

BACKGROUND: The accurate ranking of analogs of lead molecules with respect to their estimated binding free energies to drug targets remains highly challenging in molecular docking due to small relative differences in their free energy values. METHODS: Free energy perturbation (FEP) method, which provides the most accurate relative binding free energy values were earlier used to calculate free energies of many ligands for several important drug targets including Fructose-1,6-BisphosPhatase (FBPase). The availability of abundant structural and experimental binding affinity data for FBPase inhibitors provided an ideal system to evaluate four widely used docking programs, AutoDock, Glide, GOLD and SurflexDock, distinct from earlier comparative evaluation studies. RESULTS: The analyses suggested that, considering various parameters such as docking pose, scoring and ranking accuracy, sensitivity analysis and newly introduced relative ranking score, Glide provided reasonably consistent results in all respects for the system studied in the present work. Whereas GOLD and AutoDock also demonstrated better performance, AutoDock results were found to be significantly superior in terms of scoring accuracy compared to the rest. CONCLUSION: Present analysis serves as a useful guide for researchers working in the field of lead optimization and for developers in upgradation of the docking programs.

The immune response evokes changes in brain noradrenergic neurons.

A decreased noradrenaline turnover in the hypothalami of rats was observed at the peak of the immune response to sheep red blood cells. The decrease in noradrenergic neuronal activity was mimicked by injection of soluble r mediators released by immunological cells activated in vitro. Noradrenaline also tended to decrease in the brainstem but not in the residual brain. It is suggested that products released from activated immunological cells during the immune response may induce the previously described autonomic and endocrine mechanisms that contribute to immunoregulation.

Intrinsic thermal expansivity and hydrational properties of amyloid peptide Abeta42 in liquid water.

Volumetric and conformational properties of the amyloid beta(1-42) peptide (Abeta(42)) are studied in relation to the properties of hydration water in a wide temperature range by computer simulations. The apparent volume of Abeta(42), which is the change in the total volume of the solution due to the presence of Abeta(42), shows a quite different temperature dependence below and above T approximately 320 K. The apparent thermal expansion coefficient alpha(app)(Abeta(42)) is about 1.5x10(-3) K(-1) at T320 K. By evaluation of the thermal expansivity of hydration water, the intrinsic expansivity of the biomolecule in liquid water was determined for the first time. The intrinsic thermal expansion coefficient of Abeta(42) is found to be negative: alpha(int)(Abeta(42)) approximately -0.8x10(-3) K(-1). The negative thermal expansion coefficient of Abeta(42) can be attributed to its rubberlike (entropic) elasticity and/or to a decreasing number of intrapeptide hydrogen bonds. Upon heating, Abeta(42) transforms from an extended chain with a significant content of alpha-helices to a compact coil with noticeable content of beta-structures. A hydrogen-bonded spanning network of hydration water envelops Abeta(42) homogeneously at low temperatures but breaks into an ensemble of small water clusters upon heating via a percolation transition, whose midpoint is close to the temperature, where the apparent volume of Abeta(42) changes its temperature behavior. The mutual relation between the volumetric properties of Abeta(42), its conformational properties, and the properties of the hydration water is discussed.

Family-assisted inference of the genetic architecture of major histocompatibility complex variation.

With their direct link to individual fitness, genes of the major histocompatibility complex (MHC) are a popular system to study the evolution of adaptive genetic diversity. However, owing to the highly dynamic evolution of the MHC region, the isolation, characterization and genotyping of MHC genes remain a major challenge. While high-throughput sequencing technologies now provide unprecedented resolution of the high allelic diversity observed at the MHC, in many species, it remains unclear (i) how alleles are distributed among MHC loci, (ii) whether MHC loci are linked or segregate independently and (iii) how much copy number variation (CNV) can be observed for MHC genes in natural populations. Here, we show that the study of allele segregation patterns within families can provide significant insights in this context. We sequenced two MHC class I (MHC-I) loci in 1267 European barn owls (Tyto alba), including 590 offspring from 130 families using Illumina MiSeq technology. Coupled with a high per-individual sequencing coverage (~3000×), the study of allele segregation patterns within families provided information on three aspects of the architecture of MHC-I variation in barn owls: (i) extensive sharing of alleles among loci, (ii) strong linkage of MHC-I loci indicating tandem architecture and (iii) the presence of CNV in the barn owl MHC-I. We conclude that the additional information that can be gained from high-coverage amplicon sequencing by investigating allele segregation patterns in families not only helps improving the accuracy of MHC genotyping, but also contributes towards enhanced analyses in the context of MHC evolutionary ecology.

Effects of p-chlorophenylalanine on hypothalamic indoleamine levels and the associated changes which occur in catecholamine dynamics and LH surges in estrogen-treated ovariectomized rats.

Recent studies have demonstrated that the serotonergic and noradrenergic systems are functionally and anatomically linked and both systems have been implicated as contributors to the regulation of the phasic release of LH. Consequently, perturbations within the serotonergic system could secondarily affect noradrenergic system activity and result in a loss of phasic LHRH secretion. In the present studies we examined the effects of p-chlorophenylalanine (PCPA) on LH surges and the associated changes which occur in hypothalamic serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations. We also evaluated the effects of this drug on norepinephrine (NE) and dopamine (DA) initial concentrations, rate constants and turnover rates in the medial preoptic area (MPN), suprachiasmatic nuclei (SCN), paraventricular nuclei (PVN) and median eminence (ME). Seven days after ovariectomy, rats received estradiol (E2) capsules (day 0) and on day 1 some animals also received PCPA (250 mg/kg b. wt., i.p.) while the remainder served as controls. LH surges occurred in control animals but not in PCPA-treated rats on days 2, 3 and 4. PCPA produced a significant decline in 5-HT and 5-HIAA concentrations in all microdissected hypothalamic regions at 09.00 and 15.00 h on day 2. In control rats, there were no significant changes in initial concentrations of NE in the MPN, PVN and ME between 09.00 and 15.00 h with the exception of the SCN where a slight decline had occurred by 15.00 h. NE rate constants and turnover rates increased during the afternoon in controls in the MPN, SCN and ME and declined in the PVN concomitant with LH surges. PCPA had variable effects in suppressing NE initial concentrations depending upon the hypothalamic area studied and the time of day. More importantly, the drug abolished the diurnal rhythm in rate constants observed in controls and consequently, neither the MPN, SCN nor ME showed any increase in NE turnover rates in the afternoon of day 2. In contrast, a significant decline in rate constants and turnover rates occurred in the PVN of both control and PCPA-treated rats during the afternoon of day 2. DA initial concentrations declined in controls between 09.00 and 15.00 h in the MPN and ME but not in the SCN or PVN.(ABSTRACT TRUNCATED AT 400 WORDS)

[Vascular "remodeling"]. / Il "remodeling" vascolare.

Vascular remodeling means a specific organization of the vascular wall around a diminished lumen as to the before existing conditions, with consequent vascular geometry modification. This organization comes from the response of all vascular components (endothelium, muscular cells, connective component, etc.) to physical and chemical stimuli. Particular behaviour of the vascular wall has lately been pointed out, both in long known pathologies (arteriosclerosis, arterial hypertension, diabetes mellitus, arteriosclerotic aneurysms) and in situations involving both physiopathology (ischaemia-reperfusion, angiogenesis) as therapy (angioplasty).

[The concept of quality of life in cardiac failure]. / Il concetto della qualità della vita in corso di scompenso cardiaco.

Chronic congestive heart failure is a common yet devastating syndrome and is a leading cause of morbidity and mortality in the industrialised countries. The incidence and prevalence of chronic congestive heart failure is increasing, placing a growing burden on the health care system. Despite many advances in treatment for heart disease, chronic heart failure is a terminal condition with a death rate as high as that for many malignant tumours. Patients suffering from chronic congestive heart failure report a poor quality of life because of physical symptoms, functional disability, emotional and economic burdens, frequent hospitalisations, and poor prognosis. In the context of heart failure, mortality risk (prognosis quoad vitam) can be measured using a variety of physiological variables; left ventricular (LV) dysfunction plays a primary role in the pathogenesis of congestive heart failure and correlates with prognosis, but a strong quantitative relation between exercise performance and indexes of LV function has not been demonstrated. This finding underscores the importance of psychosocial interventions in improving the quality of life and care outcomes for patients with heart failure. For this reason, questionnaires of quality of life, assessed by direct patient self-reports, have recently been imposed in cardiology, they have been used specially for evaluating most treatment of cardiac failure. The refinement of a definition of quality of life improved methods to study quality of life will contribute to a better understanding of this complex concept in heart failure patients.

[Arterial hypertension in an ambulatory population of elderly subjects. Epidemiologic and clinical study in Isonzo]. / L'ipertensione arteriosa in una popolazione ambulatoriale di soggetti anziani. Studio epidemiologico e clinico nel territorio isontino.

The authors examine the clinical connotations of arterial hypertension in a geographical population of 1002 patients attending the Cardiological Outpatient Clinic of Unit no.2 in the Isonzo area (Monfalcone) using the most appropriate statistical methods, such as SPSS (Statistical Package for the Social Sciences) implemented on PC IBM AT 286, for multiple linear regression using a stepwise method. 1) Arterial hypertension was the result of a phenomenon which was striking owing to its mean value of 184.7 +/- 20.915 mmHg with equal mode and median of 180 mmHg. In the subgroup of 720 elderly patients this mean value differed slightly, 186.9 +/- 20.648 mmHg, with the same mode and median, whereas in the group of 282 adults the mean was 170.0 +/- 20.540 mmHg with a mode and median of 160 and 175 mmHg respectively. In the overall population 154 cases (15.4%) were affected by slight arterial hypertension with a mean of 158.9 mmHg, and 848 cases (84.8%) presented moderate-severe arterial hypertension with mean values of 189.4 mmHg. In elderly patients the mean rose to 190.4 mmHg whereas it was 186.3 mmHg in adults. 2) Mean age was 65.3 +/- 11.093 years: 70.7 +/- 7.396 years in older patients and 51.7 +/- 6.106 years in adults. Surface ECG showed signs of left ventricular hypertrophy in 292 elderly patients (40.5%) and 85 adults (30.0%), signs of ischemic cardiopathy due to T wave alteration in 246 elderly patients (34.1%) and 101 adults (35.7%), and due to ST tract in 340 (47.2%) and 102 (36.2%) respectively, with equal involvement of the free surface of the left ventricle. The radiographic enlargement of the cardiac shadow in elderly patients was observed in slight form in 153 cases (21.3%) and in moderate and marked form in 222 cases (30.8%), and in adults in 36 (12.8%) and 43 (15.2%) cases respectively. 3) Body weight was normal on average and equivalent to 77.3 +/- 13.578 kg, but of this series 713 cases were overweight and 237 were obese; 504 of elderly patients (70%) were pathological with 346 (48.1%) overweight and 158 (21.9%) obese, and of 209 pathological adults (74.1%), 130 (46.1%) and 79 (28.0%) were respectively overweight and obese. BMI oscillated from 1.70 to 5.60 with a mean of 2.80 +/- 0.409: from 1.70 to 4.21 in elderly patients with a mean of 2.70 +/- 0.379 and in adults from 2.00 to 5.60 with a mean of 2.90 +/- 0.460. 4) Mean cholesterolemia was 237 +/- 48.029 mg% and levels were normal in 203 cases and high in 799 subjects. Elderly patients showed the same mean level with a total of 580 pathological cases (80.5%) divided into 305 (42.3%) cases of slight hypercholesterolemia with a mean of 227.2 mg% and 275 (38.2%) severe cases with levels of 283.7 mg%. Adults presented a mean serum level of 236 +/- 47.588 mg%: 63 (22.3%) cases of normocholesterolemia, 117 (41.5%) cases of slight cholesterolemia with mean serum level of 224.8 mg%, and 102 (36.2%) severe cases with a mean level of 286.2 mg%, resulting in a total of 219 pathological cases (77.7%).

PCR-based isolation of multigene families: lessons from the avian MHC class IIB.

The amount of sequence data available today highly facilitates the access to genes from many gene families. Primers amplifying the desired genes over a range of species are readily obtained by aligning conserved gene regions, and laborious gene isolation procedures can often be replaced by quicker PCR-based approaches. However, in the case of multigene families, PCR-based approaches bear the often ignored risk of incomplete isolation of family members. This problem is most prominent in gene families with highly variable and thus unpredictable number of gene copies among species, such as in the major histocompatibility complex (MHC). In this study, we (i) report new primers for the isolation of the MHC class IIB (MHCIIB) gene family in birds and (ii) share our experience with isolating MHCIIB genes from an unprecedented number of avian species from all over the avian phylogeny. We report important and usually underappreciated problems encountered during PCR-based multigene family isolation and provide a collection of measures to help significantly improving the chance of successfully isolating complete multigene families using PCR-based approaches.

Volumetric properties of hydrated peptides: Voronoi-Delaunay analysis of molecular simulation runs.

The study of hydration, folding, and interaction of proteins by volumetric measurements has been promoted by recent advances in the development of highly sensitive instrumentations. However, the separation of the measured apparent volumes into contributions from the protein and the hydration water, V(app) = V(int) + ΔV, is still challenging, even with the detailed microscopic structural information from molecular simulations. By the examples of the amyloidogenic polypeptides hIAPP and Aß42 in aqueous solution, we analyze molecular dynamics simulation runs for different temperatures, using the Voronoi-Delaunay tessellation method. This method allows a parameter free determination of the intrinsic volume V(int) of complex solute molecules without any additional assumptions. For comparison, we also use fused sphere calculations, which deliver van der Waals and solute accessible surface volumes as special cases. The apparent volume V(app) of the solute molecules is calculated by different approaches, using either a traditional distance based selection of hydration water or the construction of sequential Voronoi shells. We find an astonishing coincidence with the predictions of a simple empirical approach, which is based on experimentally determined amino acid side chain contributions (Biophys. Chem.1999, 82, 35). The intrinsic volumes of the polypeptides are larger than their apparent volumes and also increase with temperature. This is due to a negative contribution of the hydration water ΔV to the apparent volume. The absolute value of this contribution is less than 10% of the intrinsic volume for both molecules and decreases with temperature. Essential volumetric differences between hydration water and bulk water are observed in the nearest neighborhood of the solute only, practically in the first two Delaunay sublayers of the first Voronoi shell. This also helps to understand the pressure dependence of the partial molar volumes of proteins.

Thermal expansivity of amyloid beta(16-22) peptides and their aggregates in water.

Temperature dependence of the volumetric and structural properties of Abeta(16-22) peptides (wild type and pathogenic forms) and their aggregates in water was studied by simulations. The intrinsic thermal expansion coefficient alpha(p) of peptides was evaluated by taking into account the difference between the volumetric properties of hydration and bulk water. Single peptides show mainly positive values of alpha(p) that correlates with the increasing number of intrapeptide hydrogen bonds upon heating. Negative values of alpha(p) found for large peptide aggregates may be attributed to the shrinking of voids inside aggregates with increasing temperature or to their rubber-like elasticity. The peptide surface exposed to water becomes more hydrophobic with increasing aggregate size that appears in decreasing density of hydration water and evidences a hydrophilic character of aggregation.

Isolation and characterization of 21 microsatellite markers in the barn owl (Tyto alba).

We report 21 new polymorphic microsatellite markers in the European barn owl (Tyto alba). The polymorphism of the reported markers was evaluated in a population situated in western Switzerland and in another from Tenerife, Canary Islands. The number of alleles per locus varies between two and 31, and expected heterozygosity per population ranges from 0.16 to 0.95. All loci are in Hardy-Weinberg equilibrium and no linkage disequilibrium was detected. Two loci exhibit a null allele in the Tenerife population.

Retarded development of neurons and oligodendroglia in rat forebrain produced by hyperphenylalaninemia results in permanent deficits in myelin despite long recovery periods.

The severe hypomyelination seen in the CNS of untreated phenylketonuria (PKU) patients has been suggested to be the result of a defect in the process of myelination itself. Using chronic hyperphenylalaninemia (HPA) in rats as a model of PKU we have previously shown, by immunohistochemistry, that axonal maturation as well as myelination was severely retarded. In the present study we have used image analysis techniques to quantitate changes in myelin basic protein (MBP) and 200-kDa neurofilament protein (NF-H) immunostaining in the corpus callosum and cerebral cortical grey matter of HPA rats. No difference in the density of MBP+ myelin was observed in the corpus callosum after 24 days HPA treatment although the width of the tract was much reduced. In contrast there was a deficit in NF-H immunostaining. Large deficits in both myelin and axonal maturity were seen in the cortical grey matter. Following a 6-week recovery period, despite recovery in the corpus callosum, large deficits in both MBP and NF-H were still seen in all cortical layers. Deficits in NF-H immunostaining were two to three times greater than those for MBP. On increasing the recovery period to 18 weeks significant deficits in myelin remained in layers I-III of the cortical grey matter whereas NF-H immunostaining had returned to normal levels in all layers. Our data suggest a primary effect of HPA on neuronal development, in particular axonal maturation, with a secondary hypomyelination and show that permanent deficits in myelinated axons in outer cortical layers can result when myelination is severely inhibited during a critical developmental period.

N-acetyl-L-aspartate is a major source of acetyl groups for lipid synthesis during rat brain development.

The function of N-acetyl-L-aspartate (NAA), a predominant substance in the CNS, has not yet been determined. To investigate the possible function of NAA as a lipid precursor [14C]-N-acetyl-L-aspartate (NAA) or [14C]-acetate (AcA) was injected intracerebrally into 8, 15- and 22-day-old rats. These time points were selected because NAA concentration and the activity of the NAA synthetizing enzyme L-aspartate-N-acetyltransferase (ANAT) were low in 8-day-old rats, intermediate in 15-day-old rats and high in 22-day-old rats. During an incubation period of 4 h the radioactive acetyl group of NAA is incorporated into the lipid fraction in amounts of 42.9 to 65.7% of recovered total radioactivity, increasing with the age of the rats. In contrast, radioactivity incorporated from AcA is constant for all three ages. With NAA as precursor only 7.2-9.4% of the recovered total radioactivity is incorporated into the protein fraction. With AcA as precursor 27.0-18.1% of recovered radioactivity is incorporated into the protein fraction, the amounts decreasing with age. Taking into account that in vivo NAA concentration in the brain is much higher than the AcA concentration, NAA is clearly the more efficient precursor for lipid synthesis than AcA. Further, we compared NAA and AcA as lipid precursors by analyzing the radioactivity in single lipid fractions, expressed as normalized specific incorporation or normalized incorporation. The measured differences between NAA and AcA in normalized specific and normalized incorporation of acetyl groups imply that NAA is not simply degraded to AcA before incorporated into lipids. We conclude that NAA is a major source of acetyl groups for lipid synthesis during rat brain development.

Disturbed myelinogenesis and recovery in hyperphenylalaninemia in rats: an immunohistochemical study.

Chronic hyperphenylalaninemia (HPA) in rats has been used as an experimental model of the human inborn error of metabolism phenylketonuria (PKU). Impaired brain development in PKU and HPA is reflected in reduced myelin formation. We have used immunohistochemistry, with antibodies to cell-specific antigenic markers, to investigate the cellular basis of the hypomyelination in the corpus callosum and cerebral cortex of rats made hyperphenylalaninemic from Postnatal Days 3-17. The rats were then allowed to recover until Day 59. No effects were seen on the number and differentiation pattern of ganglioside GD3-expressing glial progenitors. Myelin basic protein and 2'3'-cyclic nucleotide 3'-phosphohydrolase (CNP) immunostaining demonstrated a reduction in myelin formation in the corpus callosum and subcortical white matter at 12 and 17 days postnatal. However, numbers of CNP+ oligodendrocytes appeared normal throughout development. No reactive astrogliosis was seen at any stage. The intensity of axonal neurofilament immunostaining was reduced in the corpus callosum at 17 days. In layers II and III of the cortical gray matter there was an increase in the cell packing density and a concomitant decrease in cell body size. Myelination in the corpus callosum was rapid during the recovery period with no difference noted at Day 59. Axonal neurofilament staining also returned to normal in the corpus callosum. However, recovery became increasingly incomplete away from the corpus callosum into the cortical gray matter. Our data suggest a primary effect of HPA on axonal maturation with hypomyelination consequential upon this.

Determination of neurotransmitter systems in human cerebrospinal fluid and rat nervous tissue by high-performance liquid chromatography with on-line data evaluation.

We describe an improved high-performance liquid chromatographic method for the determination of tyrosine, 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, tryptophan and homovanillic acid in cerebrospinal fluid and nerve tissue, using the new microbore cartridges with 5 micron average particle size. The first four substances are quantified fluorometrically and the last two electrochemically. Both detectors are connected to the same integrator through a relay which can be switched as required. Data are collected in an on-line personal computer and evaluated statistically. An improvement in the method for extraction and separation of catecholamines is also reported.