Rôle de L'éthylène dans L'Accumulation de Capsidiol et la Sensibilité a Phytophthora capsici chez le Piment Traite par un Eliciteur

Role of ethylene in both the synthesis of capsidiol and the susceptibility to Phytophthora capsici of pepper treated with an elicitor With inoculated plants, there is a strong increase of ethylene, specially with Phyo 636. But, with plants inoculated and treated with G5 15 the quantities of ethylene are less important than with those ones inoculated and untreated with G5 15. After contamination (and only in this case), there is capsidiol synthesis as well wit h treated plants as with untreated ones, and the quantities are not significantly different. Generally, the level of induced resistance is higher wit h Phyo 636 (genetically resistant) than with Yolo Wonder (genetically susceptible). The adjunction of ethylene precursor (ACC) to G5 15 elicitor increases induced resistance with Yolo Wonder but decreases with Phyo 636: the inverse effect is observed when using ethylene inhibitor (AVG). It is suggested that, in the interaction Pepper—Phytophthora capsia, neither ethylene production nor capsidiol synthesis can be considered as biochemical tracers of induced resistance.     

La biosynthèse de l'acide indolyl-3-acétique en liaison avec le métabolisme du tryptophol et de l'indolyl-3-acétaldéhyde chez Rhizobium

Several indolic compounds are formed when tryptophan or tryptamine is metabolized by Rhizobium. Among these are indole-3-acetaldehyde (IAAld), tryptophol (Tr-ol), and indole-3-acetic acid (IAA). The metabolic relationship among the three compounds was investigated. The experiments were carried out either in the culture medium of growing Rhizobium cultures or in suspensions of washed bacterial cells. In neither case Tr-ol would function as a precursor of IAA, but tryptophan-2-¹⁴G gave rise to the formation of both IAA and Tr-ol. The ratio of IAA to Tr-ol depended on the experimental conditions, shaking favoring the formation of IAA. Also IAAld gave rise to the formation of IAA and Tr-ol when incubated with suspensions of washed cells. The ratio of the two compounds depended on experimental conditions such as pH value and shaking, the latter reducing the formation of Tr-ol. These results cannot be explained by the assumption of a dismutation mechanism catalyzed by a single enzymatic unit. The operation of two enzyme systems, responsible for the reduction and the oxidation, respectively, of IAAld is suggested and discussed.     

L’industrie en calcaire du site Paléolithique d’Isernia la Pineta : un modèle interprétatif de stratégie comportementale

The studies and the researches carried out in the last years on the Palaeolithic site of Isernia La Pineta have brought to consider in new way the activities realized by the human group that lived the basin of Isernia during the Middle Pleistocene offering an important key of interpretation of the behavioural strategies of the prehistoric man. The analysis of the exploitation of the raw material has confirmed the presence on the site of two different lithotypes: flint and limestone; the lithological dichotomy is related to the functional dichotomy of the raw material that seems to have conditioned the activities of the human group in different areas of the site. The necessity to deepen the study on the limestone has derived from the evidence brought to light in the last excavation campaigns of a remarkable concentration of the flaked limestone pebbles and the flake scars in some areas of the explored archeosurfaces, particularly on the 3a and on the overlooking layers. The present study has the purpose to explain the characteristics of the limestone finds both in reference to the raw material and to its state of preservation both to the technotypological evidences and its spatial distribution with the purpose to better understand the modalities of the exploitation of the raw material. The information collected until today have permitted to obtain a precise knowledge of the environmental context and the territorial resources exploited by the human group showing an opportunistic capability to find the most advantageous behavioural solution for the necessities of subsistence.     

Etude de l'action de l'acide nitreux sur le DNA transformant d'Haemophilus influenzae

Summary The action of nitrous acid on H. influenzae transforming DNA has been studied. Two of the antibiotic resistance markers studied, marker S (streptomycin) and marker N (novobiocin) show a difference in sensitivity towards nitrous acid. For these two markers, the loss of transforming activity is in accordance with a theory of transforming DNA proposed by Bresler and coll. In this theory the inactivation is related to the existence of damages that reduce the length of the donor DNA that is integrated. For the third marker studied, a K marker (kanamycin) the shape of the inactivation curve is somewhat different and shows the existence of an exponential component. The inactivation of the streptomycin-novobiocin linkage group (weakly linked markers) is additive, whereas the inactivation of the streptomycine-kanamycine group (closely linked markers) shows an overlapping effect which can be accounted for by the theory. These results are discussed in the text.Furthermore, the kinetic of induction by nitrous acid of reversible DNA molecules has been studied. This has been done by means of measurements of the transforming activity of nitrous acid treated DNA before and after heat denaturation and by hydroxylapatite chromatography of the heated DNA. It is shown that the kinetic of induction of reversibility is the same for the three unlinked markers studied. The direct estimation of the size of the crosslinked fraction indicates that the crosslinking effect of nitrous acid is not a major factor in marker inactivation.Finally, in view of our own results and of those obtained by others, we discuss the failure of nitrous acid to be mutagenic on native H. influenzae DNA. This failure, which contrasts with the result obtained on B. subtilis and Pneumococcal DNA, cannot be attributed to the existence of the nitrous induced crosslinks.     

Rôle des polyphénols dans la croissance. Définition ďun modèle expérimental chez Lycopersicum esculentum

Using young plants of Lycopersicum esculentum Mill., we attempt to define a system for a new evaluation of the physiological role of polyphenols, particularly of their regulating properties on growth and development, Exogenously supplied qoinic acid causes an important increase of the phenolic content and a reduced growth of the plants. The decrease in size is proportional to the stimulation of the phenolic pool and is equally obtained using other precursors of aromatic compounds like phenylalanine and cinnamic acid. Non-precursors of polyphenols structurally related to quinic acid are ineffective. It appears from these data that polyphenol levels and growth could be related in tomato plant and that this material would be convenient for studies on interactions between growth and polyphenols.     

Modalités de l'inhibition de la croissance et de la synthèse des acides nucléiques des plantules de blé par l'acide abscissique

The growth of wheat seedlings (Triticum sativum) is inhibited by abscisic acid (ABA). The inhibition increases with the concentration of ABA (from 10^-6M to 5 × 10^-5M) and is stronger in the case of coleoptiles and first leaves than in roots. In contrast, naphthaleneacetic acid (ANA), at 10^-5M, exerts its greatest inhibitory effect on the roots. The inhibitory effect of ABA on coleoptiles can be partially overcome by kinetin and to a much smaller degree by gibberellic acid. Neither of these two compounds, at 10^-5M, had any effect on the ABA-induced inhibition of root growth. The RNA and DNA contents per plant organ are considerably reduced after treatment of the seedlings with ABA, particularly in the coleoptiles and the first leaves. The incorporation of uracil-2-¹⁴C and uridine T (G) into RNA of treated seedlings is reduced in the case of coleoptiles and first leaves, but considerably enhanced in roots. The mechanism of the action of ABA is discussed in the light of these results.     

Etude par spectroscopie infrarouge de la transformation hélice–chaîne statistique des polypeptides. II. Etude de l'interaction de quelques polypeptides à chaînes latérales polaires avec l'acide trifluoracétique

The various polymer–acid solvation possibilities occuring in the helix–coil transition process of polypeptides with polar side chains were systematically analyzed by infrared spectroscopy. The following samples have been considered: poly-γ-benzyl-L -glutamate (PBLG), alternating poly-γ-benzyl-D ,L -glutamate (PBD-LG), and poly-β-benzyl-L -as-partate (PBLA). The behavior of the amide A, I, II, and νC?O ester absorptions of each polymer dissolved in trifluoroacetic acid–chloroform mixtures was studied in depth. The classical assumptions concerning the interaction between a polypeptide and a proton donor solvent are discussed. This interaction was previously proposed in a theoretical model of helix–coil transition. For PBLG, the spectral characteristics of the cooperative transition are evidenced by the amide bands. These bands also show main chain–acid hydrogen bonding (I) Quantitative analysis of phenomenon (I) was performed in order to localize the “binding sites” of the polymer. In agreement with the theory, only the complexation of peptide units belonging to random coil and terminal helical regions were observed. However, in contrast to the theory in which the association constants KCO and KNH of these residues are generally kept equal, the present results have shown that the main binding site is the carbonyl group (KNH ? 0 or « KCO ). The behavior of the polar side chains of these polypeptides were analyzed during the transition. Similarly to the peptide backbone, they bind the acid by hydrogen bonding (II) Furthermore, this association is more important when the side chains are localized in the coiled regions than in the helical ones. This result suggests, by analogy with the main chain behavior, that the helix–coil transition theory should take into account two more association constants for polar side chains, namely k₁ for the helical regions and k₂ > k₁ for the coiled ones.     

Approche hybride combinant champs de Markov et modèle statistique de forme pour l’extraction des contours de la prostate en IRM

Recent progress in magnetic resonance imaging (MRI) has enabled new prostate cancer diagnosis techniques. The newest challenges in this field are to enhance image-based tumours detection. In such a context, the extraction of prostate's contours is a crucial step in the interpretation of MR images, and is usually carried out by an expert radiologist. This is though a tedious time consuming task, especially in 3D images (like CT and MRI). In addition, manual delineation is not reproducible because of differences between observers. In this paper, we introduce a novel method for automatic segmentation of prostate MRI that could help physicians in extracting 3D outlines of the gland. First a deformable shape model is used to obtain a first segmentation. The latter is refined using intensity information and Markov Random Fields modelling of regions. We use the Iterative Conditional Mode for optimising voxels’ labelling according to a Maximum A Posteriori criterion. Results from evaluation on patients’ data show that the method is satisfyingly accurate, fast and robust which makes it suitable for use in a clinical context. A multicentric validation and transfer to the industry would bring the contributions of this method to clinical routine and help improving diagnosis of prostate cancer.     

Analyse conformationnelle de la N-méthylamide de l'acide L-pyroglutamique par diffusion Rayleigh depolarisée,spectroscopie de vibration et calcul de l'energie conformationnelle

Conformational analysis of N-methylamide of pyroglutamic acid has been performed by theoretical energy calculations and experimental physical techniques, namely, laser Raman spectroscopy and depolarized Rayleigh scattering. The two theoretically predicted conformations are evidenced in crystalline state (ψ₁ = +169°) and in aqueous solution (ψ₁ ? ?20°). This study confirms the interest of a careful vibrational analysis of peptides and N-deuterated derivatives for providing an estimate of the dihedral angle ψ. The relationship between amide III frequency and ψ values is emphasized.     

Apport de l’imagerie hybride TEMP-TDM dans le suivi d’un cancer différencié de la thyroïde

In the management of patients with differentiated thyroid cancer (DTC), abnormalities detected on planar whole body scan and ¹³¹I-SPECT are difficult to interpret because of a lack of anatomical landmarks and limited specificity. Integrated ¹³¹I-SPECT-CT imaging has an additional value for characterization of equivocal tracer uptake seen on planar imaging as well as for precise localization. We illustrate through an observation the incremental diagnostic value of ¹³¹I-SPECT-CT images in the diagnosis of a cervical lymph node mimicking a physiological uptake on planar views. A 35-year-old Tunisian female was followed for papillary thyroid carcinoma, for which she underwent total thyroidectomy and iratherapy. Three years after a complete remission, the thyroglobulin (Tg) level on TSH stimulation increased. Diagnostic planar images with ¹³¹I did not disclose any obvious pathological foci. Furthermore, we noticed an increased ¹³¹I-uptake in the left sub-mandibulary area, which suggested a salivary physiological activity. SPECT-CT of the neck and chest were then performed with a Symbia T camera. Fused images demonstrate that this activity corresponds to a cervical lymph node closely adjacent to sub-mandibulary gland. Management of the patient was then changed. In selected patients with DTC, hybrid imaging should be used as a complementary to planar imaging in terms of diagnostic accuracy, because of superior focus localization and additional anatomic information derived from the CT component. Integrated SPECT-CT is then a useful tool, especially in cases of unclear diagnoses, precising anatomical localization of areas of increased ¹³¹I-uptake and distinguishing malignant lesions from normal physiological uptakes. This is particularly important in an oncologic center, as ours, where we don’t yet have a positron emission tomography (PET) camera is not yet available.     

Influence de la carence hydrique sur la repartition cellulaire de l'acide ribonucleique foliaire chez le cotonnier

Water stress, induced by addition of polyethyleneglycol 600 to the nutrient solution, reduces the ribonucleic acid content of cotton leaves. The chloroplastic compartment, especially its ribosomal fraction, was most affected, even losing ribonucleic acid to the cytoplasmic compartment. Decrease of ribonucleic acid content on dehydration of leaf tissue is linked with an increase of ribonuclease.     

Analyse formelle de circuits de régulation génétique: le contrôle de l'immunité chez les bactériophages lambdoïdes

This paper is an attempt to describe and analyze in formal terms a genetic circuit which is rather complex and reasonably well disentangled: the control of immunity in lambdoid bacteriophages. Known models are expressed as logic equations, which relate the stade of activity of genes to variables of three kinds: genetic variables which describe the genotype of the organism, environmental variables like temperature and memorization variables. The value of each memorization variable (presence or absence of a gene product) is related to the value of the corresponding function (operation or not of the gene) by two characteristic time delays, an «establishment delay and a «decay delay.From the equations, one can derive matrices which facilitate comparison between models by showing which stable states are predicted by each model. Implications of current models, which had apparently remained cryptic, have been realized and experimentally tested.From the matrices, one can derive graphs which show the pathways (sequences of states) consistent with each model. These graphs are frequently branched and in these cases one has to analyze which conditions determine that one pathway rather than another one, is followed.     

Évaluation de méthodes automatiques de segmentation des volumes tumoraux en tomographie par émission de positons par comparaison avec des contours manuels réalisés par un groupe d’experts

Objective

Set up a framework for evaluating automatic segmentation methods of tumour volumes on PET images.

Patient and methods

This study was performed with PET images of 18 patients with non-Hodgkin's lymphoma. One target lesion per patient was pointed out. Each lesion was then three times manually delineated by five experts. Four automatic methods (the application of a threshold of 42% of the maximum SUV, the MIP-based method, the Daisne et al. method and the Nestle et al. method) were evaluated by comparison with the set of manual delineations.

Results

From the manual delineations, we have concluded to a moderate intra-operator variability and to a reduced interoperator reproducibility. From statistical tests performed on various quantitative criteria, there was no significant difference between the MIP-based method, the Daisne et al. method and the Nestle et al. one. The application of a threshold of 42% of the maximum SUV appears to be less efficient.

Conclusion

This work proposes a comparison and an evaluation protocol for segmentation methods. The generated data set will be distributed online for the community to simplify the evaluation of any new method of segmentation.     

L’Art mégalithique péninsulaire et l’Art mégalithique de la façade atlantique : un modèle de capillarité appliqué à l’Art post-paléolithique européen

We propose a wide concept in Megalithic Art that includes the decorations in the interior of the monuments, and also the similar graphics detected in the open air, either on rocks, on menhirs and in various spatial contexts (habitational areas, economic areas, funeral areas). The Megalithic Art so understood appears as very similar in all their regional versions. This model can’t be understood as a settling model of some groups above the other. We understand better an interpretation that advocates by the absorptive capacity and the cultural vivacity of all the implied regions. A capillarity model similar as the one, which is applied to the origin of the European producing peoples. The graphics that we analyse here, while deep expression of the symbolic thought, express strong continuity instead of remarkable breaks.     

Métastase rénale d’un carcinome vésiculaire de la thyroïde révélée par le balayage du corps entier à l’iode 131

Distant metastasis of differentiated thyroid carcinoma generally affect lung and/or bone tissue. Renal metastasis from thyroid carcinoma is extremely rare. We report a case of renal metastasis from a follicular thyroid carcinoma in a 55-year-old man, occuring 11 years after total thyroidectomy, fortuitously discovered on a whole body scan carried out after 131-iodine therapy for neck recurrence of disease. Salient features of our clinical case are the fortuitous mode of discovery the unilateral localization of metastases and especially the long time interval which separates its detection from that of the primitive tumour. This case report exemplifies the useful role of the whole body scan carried out after 131-iodine therapy better adapted to reveal often undetectable occult metastases with low dose, but also to ensure a regular and protracted follow-up of patients treated for differentiated thyroid carcinoma.