Apport de l'échographie au diagnostic de la pyélonéphrite aiguë chez l'enfant de moins de 6 ans (étude prospective à propos de 379 cas)

MONTPELLIER-BU Médecine UPM (341722108) / SudocMONTPELLIER-BU Médecine (341722104) / SudocSudocFranceF

Yield maintenance under drought: expansive growth and hydraulics also matter in reproductive organs

Yield maintenance under drought in maize (Zea mays) is associatedwith flowering synchrony which requires the rapid extensionof styles and stigma (silks) to be accessible for pollen. Wehave shown that the control of grain set under moderate waterdeficits similar to those in the field result from a developmentalprocess linked to the timing of silk growth, in opposition to thecommon view that abortion is linked to the sugar metabolismin ovaries. A switch to abortion occurs 2-3 days after first silkemergence in water-stressed plants, when silk growth stops simultaneouslyfor all ovary cohorts, and explains abortion rates indifferent treatments, genotypes and positions on the ear. Analysesof transcripts and metabolites indicate that the first molecularevents occur in silks rather than in ovaries, and involve genesaffecting expansive growth rather than sugar metabolism. Sugaravailability is preserved in ovaries until the switch to abortion,and the disruption of carbon metabolism only occurs afterwards.Hence, changes in metabolite contents, transcript amounts andenzyme activities involved in ovary sugar metabolism would bea consequence rather than a cause of the beginning of ovaryabortion. Patterns of silk growth responses to environment sharecommon features with those of leaf growth, with both kineticand genetic evidences. These findings have large consequencesfor breeding drought tolerant maize and for modelling grainyields under drought. Oury et al (2016) Plant Physiology171: 986-996 and 171: 997-1008Turc et al (2016) New Phytologist 212: 377–38

Seed abortion of maize under water deficit is linked to a developmental process and not to carbon deprivation

Seed abortion is a major cause of yield loss under water deficit in maize, thereby causing a high sensitivity of maize yield to droughts occurring at flowering time. It is usually believed that drough-tinduced seed abortion is linked to sugar deprivation because sugar feeding can relieve part of the effect of water deficit. However, the experiments that evidenced this effect involved very severe deficit, not compatible with those sensed by most plants in the field. In our experiments, a field-compatible water deficit (predawn leaf water potential of 0.4 MPa) caused 30 to 50% abortion, involving ovules located near the ear tip. Sucrose and hexose concentrations were unaffected or slightly increased by water deficit in ovules located either in the base or in the tip of ears, at four dates around silking. Activities of major enzymes, measured in the young ovules, were essentially unaffected, with a slight increase and decrease in SPS and invertase activities, respectively, under water deficit. It is therefore unlikely that tip abortion in moderate water deficit is linked to sugar deprivation. We propose an alternative mechanism based on the gradient of development within the ear. Silks are initiated with a basetip gradient of age, so the first silks to emerge are the oldest, located at the base of the ear. Our current research strongly suggests that abortion in water deficit is related to the timing of silk emergence. The latter is delayed under water deficit, so a longer period of time elapses from the first to the last silk emergence. This developmental process would explain both phenotypic variations with water deficit within a given genotype, and the difference in sensitivity between genotypes.Drought-tolerant yielding plant

Yield maintenance under drought: expansive growth and hydraulics also matter in reproductive organs

Yield maintenance under drought in maize (Zea mays) is associatedwith flowering synchrony which requires the rapid extensionof styles and stigma (silks) to be accessible for pollen. Wehave shown that the control of grain set under moderate waterdeficits similar to those in the field result from a developmentalprocess linked to the timing of silk growth, in opposition to thecommon view that abortion is linked to the sugar metabolismin ovaries. A switch to abortion occurs 2-3 days after first silkemergence in water-stressed plants, when silk growth stops simultaneouslyfor all ovary cohorts, and explains abortion rates indifferent treatments, genotypes and positions on the ear. Analysesof transcripts and metabolites indicate that the first molecularevents occur in silks rather than in ovaries, and involve genesaffecting expansive growth rather than sugar metabolism. Sugaravailability is preserved in ovaries until the switch to abortion,and the disruption of carbon metabolism only occurs afterwards.Hence, changes in metabolite contents, transcript amounts andenzyme activities involved in ovary sugar metabolism would bea consequence rather than a cause of the beginning of ovaryabortion. Patterns of silk growth responses to environment sharecommon features with those of leaf growth, with both kineticand genetic evidences. These findings have large consequencesfor breeding drought tolerant maize and for modelling grainyields under drought. Oury et al (2016) Plant Physiology171: 986-996 and 171: 997-1008Turc et al (2016) New Phytologist 212: 377–38

Seed abortion of maize under water deficit is linked to a developmental process and not to carbon deprivation

Seed abortion is a major cause of yield loss under water deficit in maize, thereby causing a high sensitivity of maize yield to droughts occurring at flowering time. It is usually believed that drough-tinduced seed abortion is linked to sugar deprivation because sugar feeding can relieve part of the effect of water deficit. However, the experiments that evidenced this effect involved very severe deficit, not compatible with those sensed by most plants in the field. In our experiments, a field-compatible water deficit (predawn leaf water potential of 0.4 MPa) caused 30 to 50% abortion, involving ovules located near the ear tip. Sucrose and hexose concentrations were unaffected or slightly increased by water deficit in ovules located either in the base or in the tip of ears, at four dates around silking. Activities of major enzymes, measured in the young ovules, were essentially unaffected, with a slight increase and decrease in SPS and invertase activities, respectively, under water deficit. It is therefore unlikely that tip abortion in moderate water deficit is linked to sugar deprivation. We propose an alternative mechanism based on the gradient of development within the ear. Silks are initiated with a basetip gradient of age, so the first silks to emerge are the oldest, located at the base of the ear. Our current research strongly suggests that abortion in water deficit is related to the timing of silk emergence. The latter is delayed under water deficit, so a longer period of time elapses from the first to the last silk emergence. This developmental process would explain both phenotypic variations with water deficit within a given genotype, and the difference in sensitivity between genotypes.Drought-tolerant yielding plant

Grain abortion under drought in maize: expansive growth and hydraulics also matter

Yield maintenance under drought in maize (Zea mays) requires the rapid extension of styles and stigma (silks) that collect pollen. We have shown that the control of grain set under moderate water deficits similar to those in the field result from a developmental process linked to the timing of silk growth, in opposition to the common view that abortion is linked to the sugar metabolism in ovaries. A switch to abortion occurs 2-3d after first silk emergence in water-stressed plants, when silk growth stops simultaneously for all ovary cohorts, and explains abortion rates in different treatments and positions on the ear. Analyses of transcripts and metabolites indicate that the first molecular events occur in silks rather than in ovaries, and involve genes affecting expansive growth rather than sugar metabolism. Sugar availability is preserved in ovaries until the switch to abortion, and the disruption of carbon metabolism only occurs afterwards. Hence, changes in metabolite contents, transcript amounts and enzyme activities involved in ovary sugar metabolism would be a consequence rather than a cause of the beginning of ovary abortion. Patterns of silk growth responses to environment share common features with those of leaf growth with both kinetic and genetic evidences. These findings have large consequences for breeding drought tolerant maize and for modelling grain yields under drought

Grain abortion under drought in maize: expansive growth and hydraulics also matter

Yield maintenance under drought in maize (Zea mays) requires the rapid extension of styles and stigma (silks) that collect pollen. We have shown that the control of grain set under moderate water deficits similar to those in the field result from a developmental process linked to the timing of silk growth, in opposition to the common view that abortion is linked to the sugar metabolism in ovaries. A switch to abortion occurs 2-3d after first silk emergence in water-stressed plants, when silk growth stops simultaneously for all ovary cohorts, and explains abortion rates in different treatments and positions on the ear. Analyses of transcripts and metabolites indicate that the first molecular events occur in silks rather than in ovaries, and involve genes affecting expansive growth rather than sugar metabolism. Sugar availability is preserved in ovaries until the switch to abortion, and the disruption of carbon metabolism only occurs afterwards. Hence, changes in metabolite contents, transcript amounts and enzyme activities involved in ovary sugar metabolism would be a consequence rather than a cause of the beginning of ovary abortion. Patterns of silk growth responses to environment share common features with those of leaf growth with both kinetic and genetic evidences. These findings have large consequences for breeding drought tolerant maize and for modelling grain yields under drought.Développer de nouvelles variétés de maïs pour une agriculture durable: une approche intégrée de la génomique à la sélectionDrought-tolerant yielding plant

Torticollis in Children

International audienc

Prenatal diagnosis of antenatal midgut volvulus: Specific ultrasound features

International audienceOBJECTIVE:To assess specific, direct, and indirect prenatal ultrasound features in cases of fetal midgut volvulus.METHODS:Retrospective case series of neonatal volvulus, based on postnatal and prenatal imaging findings that occurred from 2006-2017. Prenatal and postnatal signs including the specific "whirlpool sign" were computed. Postnatal volvulus was confirmed by pathology examination after surgery or neonatal autopsy.RESULTS:Thirteen cases of midgut volvulus were identified. Though not a specific sign, a decrease in active fetal movements was reported in eight patients (61.5%). The prenatal whirlpool sign was directly seen in 10 cases, while an indirect but suggestive sign, a fluid-filled level within the dilated loops, was present in five cases. No intestinal malrotation was observed. Pregnancy outcomes were two terminations of pregnancy, both associated with cystic fibrosis, one early neonatal death, three prenatal spontaneous regressions, and seven favorable outcomes after neonatal surgery with resection of midgut atresia.CONCLUSIONS:Identification of the whirlpool sign or of a fluid-filled level within the dilated loops improves the accuracy of ultrasound findings for suspected volvulus. In the absence of total volvulus (in cases of intestinal malrotation) or association with cystic fibrosis, the prognosis appears good

Is change in ovary carbon status a cause or a consequence of maize ovary abortion in water deficit during flowering?

Flower or grain abortion causes large yield losses under water deficit. In maize (Zea mays), it is often attributed to a carbon limitation via the disruption of sucrose cleavage by cell wall invertases in developing ovaries. We have tested this hypothesis versus another linked to the expansive growth of ovaries and silks. We have measured, in silks and ovaries of well-watered or moderately droughted plants, the transcript abundances of genes involved in either tissue expansion or sugar metabolism, together with the concentrations and amounts of sugars, and with the activities of major enzymes of carbon metabolism. Photosynthesis and indicators of sugar export, measured during water deprivation, suggested sugar export maintained by the leaf. The first molecular changes occurred in silks rather than in ovaries and involved genes affecting expansive growth rather than sugar metabolism. Changes in the concentrations and amounts of sugars and in the activities of enzymes of sugar metabolism occurred in apical ovaries that eventually aborted, but probably after the switch to abortion of these ovaries. Hence, we propose that, under moderate water deficits corresponding to most European drought scenarios, changes in carbon metabolism during flowering time are a consequence rather than a cause of the beginning of ovary abortion. A carbon-driven ovary abortion may occur later in the cycle in the case of carbon shortage or under very severe water deficits. These findings support the view that, until the end of silking, expansive growth of reproductive organs is the primary event leading to abortion, rather than a disruption of carbon metabolism.Un maïs adapté à la sécheresse : développement de l'épi et surface foliaireDrought-tolerant yielding plant