Most land plants have evolved a mutualistic symbiosis with arbuscular mycorrhiza (AM)fungi that improve nutrient acquisition from the soil.In return,up to 20% of host plant photosynthate is transferred to the mycorrhi...Most land plants have evolved a mutualistic symbiosis with arbuscular mycorrhiza (AM)fungi that improve nutrient acquisition from the soil.In return,up to 20% of host plant photosynthate is transferred to the mycorrhizal fungus in the form of lipids and sugar.Nutrient exchange must be regulated by both partners in order to maintain a reliable symbiotic relationship.However,the mechanisms underlying the regulation of lipid transfer from the plantto the AM fungus remain elusive.Here,we show that the Medicago truncatula AP2/EREBP transcription factor WRI5a,and likely its two homologs WRI5b/Erfl and WRI5c,are master regulators of AM symbiosis Controlling lipid transfer and periarbuscular membrane formation.We found that WRI5a binds AW-box cis-regulatory elements in the promoters of M.truncatula STR,which encodes a periarbuscular membrane-localized ABC transporter required for lipid transfer from the plant to the AM fungus, and MtPT4,whichr encodes a phosphate transporter required for phosphate transfer from the AM fungus to the plant.The hairy roots of the M.truncatula wti5a mutant and RNAi composite plants displayed impaired arbuscule formation,whereas overexpression of WRI5a resulted in enhanced expression of STR and MtPT4,suggesting that WRI5a regulates bidirectional symbiotic nutrient exchange.Moreover,we found that WRI5a and RAM1(Required for Arbuscular Mycorrhization symbiosis 1),which encodes a GRASdomain transcription factor,regulate each other at the transcriptional level,forming a positive feedback loop for regulatingAM symbiosis.Collectively,our data suggest a role for WRI5a in controlling bidirectional nutrient exchange and periarbuscular membrane formation via the regulation of genes involved in the biosynthesis of fatty acids and phosphate uptake in arbuscule-containing cells.展开更多
<strong>Introduction</strong>: The teenager is the one whose chronological age is between 10 and 19 years according to the World Health Organization. Pregnancy dur-ing teenage age, whether desired or not, ...<strong>Introduction</strong>: The teenager is the one whose chronological age is between 10 and 19 years according to the World Health Organization. Pregnancy dur-ing teenage age, whether desired or not, presents serious obstetric risks. The purpose of this study was to assess risk factors associated with childbirth in teenagers. <strong>Patients and Methods</strong>: This was an analytical cross-sectional study (witness case) conducted over the period from April 1st to September 30th, 2019 (6 months) in the maternity ward of the Centre Hospitalier Uni-versitaire. It was included in the study all the parturients who were presented according to the place where the pregnancy was monitored. <strong>Results</strong>: A total of 510 childbirths were recorded during the study period, we identified 157 childbirth aged under 20 (teenager), and 353 controls. The frequency of childbirth for teenage girls was 30.7%. The average age of teenage girls was 15 years with extremes of 13-19 years old. Risk factors were represented by preeclampsia, episiotomy. The low birth weight and premature birth are the most significant fetal morbidity. Conclusion: The pregnancy in teenagers is a public health issue.展开更多
This study proposes a novel scheme of a cross- correlation frequency-resolved optical gating （X-FROG） measurement for an optical based on the sum frequency arbitrary waveform （OAW） generation （SFG） effect of a p...This study proposes a novel scheme of a cross- correlation frequency-resolved optical gating （X-FROG） measurement for an optical based on the sum frequency arbitrary waveform （OAW） generation （SFG） effect of a periodically poled lithium niobate （PPLN） waveguide. Based on the SFG effect and combined with the principal component generalized projects algorithm on a matrix, the theory model of the scheme is established. Using Matlab, the proposed OAW measurement X-FROG scheme using the PPLN waveguide is simulated and studied. Simulation results show that a rectangular pulse is a suitable gate pulse because of its low errors. Moreover, the increased complexity of OAW and phase mismatch decrease measurement accuracy.展开更多
基金the National Key Research and Development Program of China (2016YFA0500502)the National Science Foundation (31730103,31522007)+1 种基金the 973 National Key Basic Research Program in China (2015CB158300) the Shanghai Rising-star Program (18QA1401600).
文摘Most land plants have evolved a mutualistic symbiosis with arbuscular mycorrhiza (AM)fungi that improve nutrient acquisition from the soil.In return,up to 20% of host plant photosynthate is transferred to the mycorrhizal fungus in the form of lipids and sugar.Nutrient exchange must be regulated by both partners in order to maintain a reliable symbiotic relationship.However,the mechanisms underlying the regulation of lipid transfer from the plantto the AM fungus remain elusive.Here,we show that the Medicago truncatula AP2/EREBP transcription factor WRI5a,and likely its two homologs WRI5b/Erfl and WRI5c,are master regulators of AM symbiosis Controlling lipid transfer and periarbuscular membrane formation.We found that WRI5a binds AW-box cis-regulatory elements in the promoters of M.truncatula STR,which encodes a periarbuscular membrane-localized ABC transporter required for lipid transfer from the plant to the AM fungus, and MtPT4,whichr encodes a phosphate transporter required for phosphate transfer from the AM fungus to the plant.The hairy roots of the M.truncatula wti5a mutant and RNAi composite plants displayed impaired arbuscule formation,whereas overexpression of WRI5a resulted in enhanced expression of STR and MtPT4,suggesting that WRI5a regulates bidirectional symbiotic nutrient exchange.Moreover,we found that WRI5a and RAM1(Required for Arbuscular Mycorrhization symbiosis 1),which encodes a GRASdomain transcription factor,regulate each other at the transcriptional level,forming a positive feedback loop for regulatingAM symbiosis.Collectively,our data suggest a role for WRI5a in controlling bidirectional nutrient exchange and periarbuscular membrane formation via the regulation of genes involved in the biosynthesis of fatty acids and phosphate uptake in arbuscule-containing cells.
文摘<strong>Introduction</strong>: The teenager is the one whose chronological age is between 10 and 19 years according to the World Health Organization. Pregnancy dur-ing teenage age, whether desired or not, presents serious obstetric risks. The purpose of this study was to assess risk factors associated with childbirth in teenagers. <strong>Patients and Methods</strong>: This was an analytical cross-sectional study (witness case) conducted over the period from April 1st to September 30th, 2019 (6 months) in the maternity ward of the Centre Hospitalier Uni-versitaire. It was included in the study all the parturients who were presented according to the place where the pregnancy was monitored. <strong>Results</strong>: A total of 510 childbirths were recorded during the study period, we identified 157 childbirth aged under 20 (teenager), and 353 controls. The frequency of childbirth for teenage girls was 30.7%. The average age of teenage girls was 15 years with extremes of 13-19 years old. Risk factors were represented by preeclampsia, episiotomy. The low birth weight and premature birth are the most significant fetal morbidity. Conclusion: The pregnancy in teenagers is a public health issue.
文摘This study proposes a novel scheme of a cross- correlation frequency-resolved optical gating （X-FROG） measurement for an optical based on the sum frequency arbitrary waveform （OAW） generation （SFG） effect of a periodically poled lithium niobate （PPLN） waveguide. Based on the SFG effect and combined with the principal component generalized projects algorithm on a matrix, the theory model of the scheme is established. Using Matlab, the proposed OAW measurement X-FROG scheme using the PPLN waveguide is simulated and studied. Simulation results show that a rectangular pulse is a suitable gate pulse because of its low errors. Moreover, the increased complexity of OAW and phase mismatch decrease measurement accuracy.
