Characterization of a Pinus pinaster cDNA encoding an auxin up-regulated putative peroxidase in roots

As part of a study to identify host plant genes regulated by fungal auxin during ectomycorrhiza formation, we differentially screened a cDNA library constructed from roots of auxin-treated Pinus pinaster (Ait.) Sol. seedlings. We identified three cDNAs up-regulated by auxin. Sequence analysis of one of these cDNAs, PpPrx75, revealed the presence of an open reading frame of 216 amino acids with the characteristic consensus sequences of plant peroxidases. The deduced amino acid sequence showed homology with Arabidopsis thaliana (L.) Heynh., Arachis hypogaea L. and Stylosanthes humilis HBK cationic peroxidases. Amino acid sequence identities in the conserved domains of plant peroxidases ranged from 60 to 100%. In PpPrx75, there are five cysteine residues and one histidine residue that are found at conserved positions among other peroxidases. A potential glycosylation site (NTS) is present in the deduced sequence. Phylogenetic analysis showed that PpPrx75 is closely related to two A. thaliana peroxidases. The PpPrx75 cDNA was induced by active auxins, ethylene, abscisic acid and quercetin, a flavonoid possibly involved in plant-microorganism interactions. Transcript accumulation was detected within 3 h following root induction by auxin, and the amount of mRNA increased over the following 24 h. The protein synthesis inhibitor cycloheximide did not inhibit indole-3-acetic acid-induced transcript accumulation, suggesting that PpPrx75 induction is a primary (direct) response to auxin. This cDNA can be used to study expression of an auxin-regulated peroxidase during ectomycorrhiza formation.

[Delayed hypersensitivity to heparins and heparinoids]

Delayed hypersensitivity to heparins and heparinoïd is a problem for prophylaxis of thrombo embolic diseases. The hirudins did not seem to have any cross-reactivity with the two others groups of anticoagulants. We present two clinical cases of delayed type reactions to heparins and heparinoïd and we reviewed the literature about adverse reactions to low molecular weight heparins and the alternative possibilities.

Study of the relationship between pre-harvest sprouting and grain color by quantitative trait loci analysis in a whitexred grain bread-wheat cross

In many wheat ( Triticum aestivumL.) growing areas, pre-harvest sprouting (PHS) may cause important damage, and in particular, it has deleterious effects on bread-making quality. The relationship between PHS and grain color is well known and could be due either to the pleiotropic effect of genes controlling red-testa pigmentation ( R) or to linkage between these genes and other genes affecting PHS. In the present work, we have studied a population of 194 recombinant inbred lines from the cross between two cultivars, 'Renan' and 'Récital', in order to detect QTLs for both PHS resistance and grain color. The variety 'Renan' has red kernels and is resistant to PHS, while 'Récital' has white grain and is highly susceptible to PHS. A molecular-marker linkage map of this cross was constructed using SSRs, RFLPs and AFLPs. The population was evaluated over 2 years at Clermont-Ferrand (France). PHS was evaluated on mature spikes under controlled conditions and red-grain color was measured using a chromameter. Over the 2 years, we detected four QTLs for PHS, all of them being co-localized with QTLs for grain color. Three of them were located on the long arm of chromosomes 3 A, 3B and 3D, close to the loci where the genes R and taVp1 were previously mapped. For these three QTLs, the resistance to PHS is due to the allele of the variety 'Renan'. Another co-located QTL for PHS and grain color was detected on the short arm of chromosome 5 A. The resistance for PHS for this QTL is due to the allele of 'Récital'.

Fungal auxin overproduction affects the anatomy of Hebeloma cylindrosporum-Pinus pinaster ectomycorrhizas

We studied the effect of fungal auxin overproduction on the growth polarity of cortical cells in pine mycorrhizas by comparing the anatomy of Pinus pinaster (Ait.) Sol. mycorrhizas formed by an IAA-overproducing mutant of Hebeloma cylindrosporum Romagnesi or by the corresponding wild type with non-mycorrhizal short roots. Both wild- type and mutant strains induced an increase in root diameter that was mostly a result of the influence of the fungus on root cortical development. Both strains affected growth polarity of P. pinaster cortical cells and induced a change in their shape. The main modifications were a large reduction in axial diameter and an increase in the radial diameter of the cortical cells. The modifications were more marked with the mutant than with the wild type. The mutant induced a 43% reduction in cortical cell elongation and a 35% increase in radial diameter, whereas the corresponding changes induced by the wild type were 30 and 10%, respectively. The volume of cortical cells in mature mycorrhizas was generally lower than in uninoculated short roots indicating that wild-type and mutant strains induced a reorientation of cortical cell growth but did not induce an increase in turgor pressure of the cells. Immunolocalization allowed visualization of alpha-tubulin in root cortical cells, but no obvious modification in alpha-tubulin distribution was detected as a consequence of symbiosis establishment. Likewise, cytochemical localization of polysaccharides in cortical cell walls did not show significant modification following symbiosis establishment and Hartig net formation. The only noticeable modification was a reduction in cortical cell wall thickness in mycorrhizas compared with uninoculated short roots. The possible involvement of fungal auxin in the observed modifications is discussed.

[Fatal anaphylaxis after eating wild boar meat in a patient with pork-cat syndrome]

Crossed allergy between pork and cat epithelia was described by us in 1994. It is due to serum albumin. Nowadays, other bio-chemical observations allow "completion" of the syndrome by extension of the crossed reactivity between other mammal meats and other epithelia of dog and horse. The authors report an observation of the pork-cat syndrome (developing in the form of anaphylaxis, and then ending in the death of the patient), following consumption of wild boar meat. Co-factors, such as effort, taking alcohol or hormonal condition may complicate the picture to make diagnosis more difficult.

Transcription of a nitrate reductase gene isolated from the symbiotic basidiomycete fungus Hebeloma cylindrosporum does not require induction by nitrate

Ectomycorrhizal fungi contribute to the nitrogen nutrition of their host plants, but no information is available on the molecular control of their nitrogen metabolism. The cloning and pattern of transcriptional regulation of two nitrite reductase genes of the symbiotic basidiomycete Hebeloma cylindrosporum are presented. The genomic copy of one of these genes (nar1) was entirely sequenced; the coding region is interrupted by 12 introns. The nar1 gene, which is transcribed and codes for a putative 908-amino acid polypeptide complemented nitrate reductase-deficient mutants of H. cylindrosporum upon transformation, thus demonstrating that the gene is functional. The second gene (nar2), for which no mRNA transcripts were detected, is considered to be an ancestral, non-functional duplication of nar1. In a 462-nt partial sequence of nar2 two introns were identified at positions identical to those of introns 8 and 9 of nar1, although their respective nucleotide sequences were highly divergent; the exon sequences were much more conserved. In wild-type strains, transcription of nar1 is repressed in the presence of a high concentration of ammonium. High levels of transcription are observed in the presence of either very low nitrogen concentrations or high concentrations of nitrate or organic N sources such as urea, glycine or serine. This indicates that in H. cylindrosporum, in contrast to all nitrophilous organisms studied so far, an exogenous supply of nitrate is not required to induce transcription of a nitrate reductase gene. In contrast, repression by ammonium suggests the existence of a wide-domain regulatory gene, as already characterized in ascomycete species.

Dynamics of symbiotic establishment between an IAA-overproducing mutant of the ectomycorrhizal fungus Hebeloma cylindrosporum and Pinus pinaster

To clarify the early steps of symbiotic establishment, we studied the dynamics of Pinus pinaster (Ait.) Sol. tap root colonization and mycorrhiza formation by an IAA-overproducing mutant of the ectomycorrhizal fungus Hebeloma cylindrosporum Romagnesi and by the corresponding wild type strain. Differences between wild type and mutant strains were quantitative rather than qualitative and were detected two days after inoculation. Both fungal strains established a typical Hartig net when they colonized the tap roots. Consequently, colonized tap roots exhibited features of a true mycorrhiza and fungal colonization enhanced plant growth. Fungal colonization and Hartig net formation were more rapid with the mutant than with the wild type. Colonization, especially with the mutant strain, increased rhizogenesis and the production of mycorrhizas. The mutant formed a hypertrophic Hartig net in tap roots and mycorrhizal short roots and we obtained evidence that the process of short root transformation into mycorrhiza started before their emergence from the tap root. Hyphae of the Hartig net in the tap root penetrated the cortex of young lateral roots at the beginning of their elongation, after the endodermis layer broke under the pressure of the elongating lateral root. Colonization was inhibited when triiodobenzoic acid was added to the culture medium, providing circumstantial evidence that auxin is involved in mycorrhiza formation.

Comparison among 18 hexyl esters of 1-naphthylacetic acid used on grapevine

Eighteen esters derived from 1-naphthylacetic acid (NAA) and from hexyl isomer alcohols were synthesized and sprayed on grapevine suckers at 1, 2, 4, and 8% w/w concentrations to test their sucker control efficiency 2, 10, and 30 days and 1 year after their application. All compounds gave a prompt control of suckers. After 1 year, sucker growth was inhibited by the derivatives from primary and secondary alcohols, whereas the number of suckers was reduced only by application of naphthyl acetates of tertiary alcohols.

[Chronic urticaria caused by cow's milk allergy: immediate or delayed allergy? (apropos of a case)]

Chronic urticaria has multiple etiologies, amongst them food allergy, which is not the most frequent. We report a clinical case of chronic urticaria due to cow milk, where paradoxically the responsibility of the food was shown by an epidermo test when the prick test was negative. Development confirmed the responsibility of cow milk. We discuss the mechanisms that relate chronic urticaria to delayed hypersensitivity.

The auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) inhibits the stimulation of in vitro lateral root formation and the colonization of the tap-root cortex of Norway spruce (Picea abies) seedlings by the ectomycorrhizal fungus Laccaria bicolor

Norway spruce (Picea abies (L.) Karst.) seedlings were inoculated with the ectomycorrhizal fungus Laccaria bicolor ((Marie) Orton), strain S238 N, in axenic conditions. The presence of the fungus slowed tap-root elongation by 26% during the first 15 d after inoculation and then stimulated it by 136%. In addition, it multiplied in vitro lateral root formation by 4.3, the epicotyl growth of the seedlings by 8.4 and the number of needles by 2. These effects were maintained when the fungus was separated from the roots by a cellophane membrane preventing symbiosis establishment, thus suggesting that the fungus acted by non-nutritional effects. We tested the hypothesis that IAA produced by L. bicolor S238 N would be responsible for the stimulation of fungal induced rhizogenesis. We showed in previous work that L. bicolor S238 N can synthesize IAA in pure culture. Exogenous IAA supplies (100 and 500 μm) reproduced the stimulating effect of the fungus on root branching but inhibited root elongation. The presence of 2,3,5-triiodobenzoic acid (TIBA) in the culture medium significantly depressed lateral root formation of inoculated seedlings. As TIBA had no significant effect on IAA released in the medium by L. bicolor S238 N, but counteracted the stimulation of lateral rhizogenesis induced by an exogenous supply of IAA, we suggest that TIBA inhibited the transport of fungal IAA in the root. Furthermore TIBA blocked the colonization of the main root cortex by L. bicolor S238 N and the formation of the Hartig net. These results specified the role of fungal IAA in the stimulation of lateral rhizogenesis and in ectomycorrhizal symbiosis establishment.

[Treatment and prevention of food allergy]

Treatment of food allergy is above all etiological, and needs suppression of the food on condition: that it has been proven to be responsible, that it is not indispensible to nutrition. The etiological treatment may be associated with drug treatment: the anaphylactic reaction can be treated with adrenalin and corticosteroids, then chronic food allergy may be prevented or treated by: Sodium cromoglycate (Nalcron, Intercron). Ketotifen (Zaditen). Second generation anti-H1 that has a stronger anti-allergic action (Cetrizine, Loratidine). Immunotherapy or really habituation to the food is possible in some cases, but progress by ingestion of the food may be extremely slow. Prevention includes: Food of the pregnant and nursing woman: the mother should have a varied diet without excessive consumption of any food. For atopic infants diversification of foods should be late. Information to parents is essential.

[Treatment and prevention of food allergy]

Treatment of food allergy is above all etiological, and needs suppression of the food on condition: that it has been proven to be responsible, that it is not indispensible to nutrition. The etiological treatment may be associated with drug treatment: the anaphylactic reaction can be treated with adrenalin and corticosteroids, then chronic food allergy may be prevented or treated by: Sodium cromoglycate (Nalcron, Intercron). Ketotifen (Zaditen). Second generation anti-H1 that has a stronger anti-allergic action (Cetrizine, Loratidine). Immunotherapy or really habituation to the food is possible in some casas, but progress by ingestion of the food may be extremely slow. Prevention includes: Food of the pregnant and nursing woman: the mother should have a varied diet without excessive consumption of any food. For atopic infants diversification of foods should be late. Information to parents is essential.

A generalization of the mixture model in the mapping of quantitative trait loci for progeny from a biparental cross of inbred lines

The recent advent of molecular markers has created a great potential for the understanding of quantitative inheritance. In parallel to rapid developments and improvements in molecular marker technologies, biometrical models have been constructed, refined and generalized for the mapping of quantitative trait loci (QTL). However, current models present restrictions in terms of breeding designs to which they apply. In this paper, we develop an approach for the generalization of the mixture model for progeny from a single bi-parental cross of inbred lines. Detailed derivations are given for genetic designs involving populations developed by selfing, i.e., where marker genotypes are obtained from Fx (x > or = 2) individuals and where phenotypes are measured on Fy (y > or = x) individuals or families. Extensions to designs involving doubled-haploids, backcross-derived individuals and random matings are outlined. The derivations presented here can easily be combined with current QTL mapping approaches.