A genetic linkage map of Pacific white shrimp (<Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>): sex-linked microsatellite markers and high recombination rates

Pacific white shrimp (Litopenaeus vannamei) is the leading species farmed in the Western Hemisphere and an economically important aquaculture species in China. In this project, a genetic linkage map was constructed using amplified fragment length polymorphism (AFLP) and microsatellite markers. One hundred and eight select AFLP primer combinations and 30 polymorphic microsatellite markers produced 2071 markers that were polymorphic in either of the parents and segregated in the progeny. Of these segregating markers, 319 were mapped to 45 linkage groups of the female framework map, covering a total of 4134.4 cM; and 267 markers were assigned to 45 linkage groups of the male map, covering a total of 3220.9 cM. High recombination rates were found in both parental maps. A sex-linked microsatellite marker was mapped on the female map with 6.6 cM to sex and a LOD of 17.8, two other microsatellite markers were also linked with both 8.6 cM to sex and LOD score of 14.3 and 16.4. The genetic maps presented here will serve as a basis for the construction of a high-resolution genetic map, quantitative trait loci (QTLs) detection, marker-assisted selection (MAS) and comparative genome mapping.     

QTL analysis of resistance to sharka disease in the apricot (Prunus armeniaca L.) ‘Polonais’ × ‘Stark Early Orange’ F1 progeny

Different hypotheses on the genetic control of the resistance to the plum pox virus (PPV) have been reported in apricot, but there was a lack of agreement about the number of loci involved. In recent years, apricot genetic maps have been constructed from progenies derived from ‘Stark Early Orange’ or ‘Goldrich’, two main sources of resistance, three of these including the mapping of the PPV resistance loci. As the location of the locus was not precisely established, we mapped the PPV resistance loci using interval mapping (IM), composite interval mapping (CIM), and the Kruskal–Wallis non-parametric test in the F₁ progeny derived from a cross between the susceptible cv. ‘Polonais’ and ’Stark Early Orange’. Four genomic regions were identified as being involved in PPV resistance. One of these mapped to the upper region of linkage group 1 of ‘Stark Early Orange’, and accounted for 56% of the phenotypic variation. Its location was similar to the one previously identified in ‘Goldrich’ and Prunus davidiana. In addition, a gene strongly associated to these major quantitative trait loci (QTL) was found to be related to PPV infection. Two putative QTLs were detected on linkage groups 3 of ‘Polonais’ and 5 of both ‘Polonais’ and ‘Stark Early Orange’ with both parametric and non-parametric methods at logarithm of odds (LOD) scores slightly above the detection threshold. The last QTL was only detected in the early stage of the infection. PPV resistance is, thus, controlled by a major dominant factor located on linkage group 1. The hypothesis of recessive factors with lower effect is discussed.     

Proteome map of normal rat retina and comparison with the proteome of diabetic rat retina: new insight in the pathogenesis of diabetic retinopathy

We have employed proteomics to establish a proteome map of the normal rat retina. This baseline map was then used for comparison with the early diabetic rat retinal proteome. Diabetic rat retinae were obtained from Dark Agouti rats after 10 wk of streptozotocin-induced hyperglycaemia. Extracted proteins from normal and diabetic rat retinae were separated and compared using 2-DE. A total of 145 protein spots were identified in the normal rat retina using MALDI-MS and database matching. LC-coupled ESI-MS increased the repertoire of identified proteins by 23 from 145 to 168. Comparison with early diabetic rat retinae revealed 24 proteins unique to the diabetic gels, and 37 proteins absent from diabetic gels. Uniquely expressed proteins identified included the HSPs 70.1A and 8, and platelet activating factor. There were eight spots with increased expression and 27 with decreased expression on diabetic gels. Beta catenin, phosducin and aldehyde reductase were increased in expression in diabetes whilst succinyl coA ligase and dihydropyrimidase-related protein were decreased. Identification of such changes in protein expression has given new insights and a more comprehensive understanding of the pathogenesis of diabetic retinopathy, widening the scope of potential avenues for new therapies for this common cause of blindness.     

Epitope mapping the Fim2 and Fim3 proteins of Bordetella pertussis with sera from patients infected with or vaccinated against whooping cough

Abstract Antibody-binding epitopes on the Fim2 and Fim3 proteins of Bordetella pertussis , which have been associated with the induction of protective antibody, were located using sera from 12 patients with whooping cough and 4 vaccinated children. Fifteen epitopes were identified on both Fim2 and Fim3. In each case 9 were recognised by serum antibody from 11 or more infected patients. Epitopes associated with the highest IgG activity were not the same as those associated with the highest IgA activity. None of the vaccinated patients had detectable IgA. Most epitopes showed little or no evidence of serotype-specific responses, suggesting this is largely directed towards conformational epitopes. The reactivity of all but two epitopes was confirmed in an ELISA with patients' sera in which epitopes were re-synthesised as free soluble peptides. The short linear epitopes described may therefore be useful in the development of serodiagnostic assays but are unlikely vaccine candidates.     

我国动物地理学研究的前景─—方法论探讨

本文着重从方法论的角度探讨在新形势下我国动物地理学的前景，提出建立两类资料地图──动物学资料图（ Ｚｏｏｌｏｇｉｃａｌ　ｉｎｆｏｒｍａｔｉｏｎ　ｍａｐ）和地理学资料图（Ｇｅｏｇｒａｐｈｉｃａｌ ｉｎｆｏｒｍａｔｉｏｎ ｍａｐ），以比较地理学分析法（Ｃｏｍｐａｒａｔｉｖｅ ｇｅｏｇｒａｐｈｉｃａｌ ａｎａｌｙｓｉｓ），进行不同时空尺度的研究，并建议了在最近时期内应优先选择开展研究的关键性地区及其中心问题。     

Mapping QTLs controlling fruit quality in peach (Prunus persica (L.) Batsch)

 The organoleptic quality of fleshy fruits is in a large part defined by their composition of soluble sugars and organic acids. An F₂ population issuing from a cross between two peach varieties, ‘Ferjalou Jalousia’, a non-acid peach, and ‘Fantasia’, an acid nectarine, was analysed over 2 successive years for agronomic characters and for molecular-marker (isoenzymes, RFLPs, RAPDs, IMAs and AFLPs) segregations. Blooming and maturity dates, as well as productivity, were noted for each tree. Four fruits per tree were analysed at maturity for fresh weight, colour, pH, titratable acidity, soluble-solids content (SSC), acid (malic, citric and quinic acids) and sugar (sucrose, glucose, fructose, sorbitol) contents. QTLs were detected for all fruit components analysed, except for fruit colour. The QTLs for nearly all components were present on two linkage groups. For productivity, fresh weight, pH, quinic acid, sucrose and sorbitol content, all the detected QTLs displayed the same effect as the parental phenotypes. By contrast, for maturity date, titratable acidity, malic and citric acids and fructose, some QTLs displayed the same effect as the parental phenotypes while others displayed the opposite effect. The fraction of the total variation in each trait throughout the population explained by the QTLs was very high and reached more than 90% for some characters. For most of the characters analysed, epistasis was observed between QTLs. Received: 10 October 1997 / Accepted: 18 August 1998     

Glucose-induced period-doubling cascade in the electrical activity of pancreatic β-cells

 In the presence of stimulatory concentrations of glucose, the membrane potential of pancreatic β-cells may experience a transition from periods of rapid spike-like oscillations alternating with a pseudo-steady state to spike-only oscillations. Insulin secretion from β-cells closely correlates the periods of spike-like oscillations. The purpose of this paper is to study the mathematical structure which underlines this transitional stage in a pancreatic β-cell model. It is demonstrated that the transition can be chaotic but becomes more and more regular with increase in glucose. In particular, the system undergoes a reversed period-doubling cascade leading to the spike-only oscillations as the glucose concentration crosses a threshold. The transition interval in glucose concentration is estimated to be extremely small in terms of the rate of change for the calcium dynamics in the β-cells. The methods are based on the theory of unimodal maps and the geometric and asymptotic theories of singular perturbations. Received: 25 October 1996/Revised version: 18 August 1997     

Comparative analysis and development of microsatellite markers on swine (Sus scrofa) chromosome 1qter

Several quantitative trait loci (QTL) have been detected on SSC1qter (Sus scrofa chromosome 1qter), including QTL for the number of vertebrae, as reported in our previous study. To provide the tools for analysis of QTLs on SSC1qter, we constructed a comparative map of swine and human. In addition, we identified 26 swine STSs and mapped 16 of them on SSC1qter using the INRA - University of Minnesota porcine radiation hybrid (IMpRH) panel. We screened a BAC library using these swine STSs and developed 35 new polymorphic microsatellite markers from the BAC clones, of which 26 were informative in our reference family. We also mapped nine microsatellite markers we had isolated previously. Consequently a total of 44 new polymorphic microsatellite markers were located within a 60-cM region of SSC1qter, spanning from SW1092 to the telomere.     

Modelling the distributions of Culicoides bluetongue virus vectors in Sicily in relation to satellite-derived climate variables

Surveillance data from 268 sites in Sicily are used to develop climatic models for prediction of the distribution of the main European bluetongue virus (BTV) vector Culicoides imicola Kieffer (Diptera: Ceratopogonidae) and of potential novel vectors, Culicoides pulicaris Linnaeus, Culicoides obsoletus group Meigen and Culicoides newsteadi Austen. The models containing the 'best' climatic predictors of distribution for each species, were selected from combinations of 40 temporally Fourier-processed remotely sensed variables and altitude at a 1 km spatial resolution using discriminant analysis. Kappa values of around 0.6 for all species models indicated substantial levels of agreement between model predictions and observed data. Whilst the distributions of C. obsoletus group and C. newsteadi were predicted by temperature variables, those of C. pulicaris and C. imicola were determined mainly by normalized difference vegetation index (NDVI), a variable correlated with soil moisture and vegetation biomass and productivity. These models were used to predict species presence in unsampled pixels across Italy and for C. imicola across Europe and North Africa. The predicted continuous presence of C. pulicaris along the appenine mountains, from north to south Italy, suggests BTV transmission may be possible in a large proportion of this region and that seasonal transhumance (seasonal movement of livestock between upland and lowland pastures) even in C. imicola-free areas should not generally be considered safe. The predicted distribution of C. imicola distribution shows substantial agreement with observed surveillance data from Greece and Iberia (including the Balearics) and parts of mainland Italy (Lazio, Tuscany and areas of the Ionian coast) but is generally much more restricted than the observed distribution (in Sardinia, Corsica and Morocco). The low number of presence sites for C. imicola in Sicily meant that only a restricted range of potential C. imicola habitats were included in the training set and that predictions could only be made within this range. Future modelling exercises will use abundance data collected according to a standardized protocol across the Mediterranean and, for Sicily in particular, should include non-climatic environmental variables that may influence breeding site suitability such as soil type.     

Relationships between amino acid sequence and backbone torsion angle preferences

Statistical averages and correlations for backbone torsion angles of chymotrypsin inhibitor 2 are calculated by using the Rotational Isomeric States model of chain statistics. Statistical weights of torsional states of phipsi pairs, needed for the statistics of the full chain, are obtained in two different ways: 1) by using knowledge-based pairwise dependent phipsi energy maps from Protein Data Bank (PDB) and 2) by collecting torsion angle data from a large number of random coil configurations of an all-atom protein model with volume exclusion. Results obtained by using PDB data show strong correlations between adjacent torsion angle pairs belonging to both the same and different residues. These correlations favor the choice of the native-state torsion angles, and they are strongly context dependent, determined by the specific amino acid sequence of the protein. Excluded volume or steric clashes, only, do not introduce context-dependent phipsi correlations into the chain that would affect the choice of native-state torsional angles.