Irrigation regimes modulate non-structural carbohydrate remobilization and improve grain filling in rice(Oryza sativa L.)by regulating starch metabolism

Recently developed ‘super’ rice cultivars with greater yield potentials often suffer from the problem of poor grain filling, especially in inferior spikelets. Here, we studied the activities of enzymes related to starch metabolism in rice stems and grains, and the microstructures related to carbohydrate accumulation and transportation to investigate the effects of different water regimes on grain filling. Two ‘super’ rice cultivars were grown under two irrigation regimes of well-watered(WW) and alternate wetting and moderate soil drying(AWMD). Compared with the WW treatment,the activities of ADP glucose pyrophosphorylase(AGPase), starch synthase(StSase) and starch branching enzyme(SBE), and the accumulation of non-structural carbohydrates(NSCs) in the stems before heading were significantly improved, and more starch granules were stored in the stems in the AWMD treatment. After heading, the activities of α-amylase, β-amylase, sucrose phosphate synthase(SPS) and sucrose synthase in the synthetic direction(SSs)were increased in the stems to promote the remobilization of NSCs for grain filling under AWMD. During grain filling, the enzymatic activities of sucrose synthase in the cleavage direction(SSc), AGPase, StSase and SBE in the inferior spikelets were increased, which promoted grain filling, especially for the inferior spikelets under AWMD.However, there were no significant differences in vascular microstructures. The grain yield and grain weight could be improved by 13.1 and 7.5%, respectively, by optimizing of the irrigation regime. We concluded that the low activities of key enzymes in carbon metabolism is the key limitation for the poor grain filling, as opposed to the vascular microstructures, and AWMD can increase the amount of NSC accumulation in the stems before heading, improve the utilization rate of NSCs after heading, and increase the grain filling, especially in the inferior spikelets, by altering the activities of key enzymes in carbon metabolism.

Allergen degradation of bee pollen by lactic acid bacteria fermentation and its alleviatory effects on allergic reactions in BALB/c mice

Food allergy as a global health problem threatens food industry.Bee pollen(BP)is a typical food with allergenic potentials,although it performs various nutritional/pharmacological functions to humans.In this study,lactic acid bacteria(LAB)were used to ferment Brassica napus BP for alleviating its allergenicity.Four novel allergens(glutaredoxin,oleosin-B2,catalase and lipase)were identified with significant decreases in LAB-fermented BP(FBP)than natural BP by proteomics.Meanwhile,metabolomics analysis showed significant increases of 28 characteristic oligopeptides and amino acids in FBP versus BP,indicating the degradation of LAB on allergens.Moreover,FBP showed alleviatory effects in BALB/c mice,which relieved pathological symptoms and lowered production of allergic mediators.Microbial high-throughput sequencing analysis showed that FBP could regulate gut microbiota and metabolism to strengthen immunity,which were closely correlated with the alleviation of allergic reactivity.These findings could contribute to the development and utilization of hypoallergenic BP products.

Characterization of physicochemical and immunogenic properties of allergenic proteins altered by food processing:a review

Food allergens are mainly naturally-occurring proteins with immunoglobulin E(IgE)-binding epitopes.Understanding the structural and immunogenic characteristics of allergenic proteins is essential in assessing whether and how food processing techniques reduce allergenicity.We here discuss the impacts of food processing technologies on the modification of physicochemical,structural,and immunogenic properties of allergenic proteins.Detection techniques for characterizing changes in these properties of food allergens are summarized.Food processing helps to reduce allergenicity by aggregating or denaturing proteins,which masks,modifies,or destroys antigenic epitopes,whereas,it cannot eliminate allergenicity completely,and sometimes even improves allergenicity by exposing new epitopes.Moreover,most food processing techniques have been tested on purified food allergens rather than food products due to potential interference of other food components.We provide guidance for further development of processing operations that can decrease the allergenicity of allergenic food proteins without negatively impacting the nutritional profile.

Hot-top direct chill casting assisted by a twin-cooling field:Improving the ingot quality of a large-size 2024 Al alloy

Microstructure inhomogeneity and negative segregation have long been challenges for large-size alloy ingots,directly affecting the downstream processing and final performance of products.Here,we used2024 aluminum alloy as a model alloy to propose a technique,named double-cooling field casting,i.e.,one 2024 Al alloy rod(Φ20 mm)at room temperature was introduced into the melt along the central axis of the hot-top with the protection of a thermal-insulation tube during the direct chill(DC)casting process of aΦ300 mm 2024 Al alloy ingot.The results show that the introduction of the same alloy solid insert has a remarkable influence on refining grains in the center region of the ingot,reducing negative centerline segregation and decreasing the depth of the center part of the sump.With the application of the 2024 Al insert,the mean size of equiaxed grains at the center part of the ingot decreased from1204±132μm to 721±69μm.The relative deviation of the Cu and Mg main solutes reduced from-0.062 and-0.054 to-0.03 and-0.024,respectively,and the sump depth decreased from 280 mm to242 mm.Moreover,the shape of the solidification front was changed from‘V’-shaped to‘W’-shaped.The ingot quality was thus improved,mainly arising from the dissolution of the cold 2024 Al insert at a proper position of the hot-top counteracting some latent heat of solidification of the ingot,dissipating the heat of the central part of the hot-top by conducting the 2024 Al insert to the outside,and providing extra-nuclei from the unmoltenα-Al particles of the insert.

Transthoracic Salus Valve Feasibility Study: Short-Term Outcomes of a Transcatheter Self-Expandable Pulmonary Valve

Objective:The size and morphology of the right ventricular outflow tract(RVOT)in patients suffering from long-term pulmonary regurgitation(PR)after native RVOT(NRVOT)reconstruction are important factors affecting the feasibility,safety,and effectiveness of transcatheter pulmonary valve replacement.The purpose of this study was to evaluate the feasibility,safety,and effectiveness of a transthoracic Salus valve(Balance Medical Technology Co.,Ltd,Beijing,China)in patients with moderate-to-severe PR after NRVOT reconstruction.Methods:Patients with moderate-to-severe PR after NRVOT reconstruction were selected between June 2021 and November 2021 at Beijing Anzhen Hospital.Demographic data as well as preoperative,intraoperative,and follow-up data were reviewed.Results:Ten patients with moderate-to-severe PR after NRVOT reconstruction underwent physical examination,transthoracic echocardiography,and cardiovascular magnetic resonance imaging.Seven patients were selected for transthoracic Salus valve replacement.Six patients underwent implantation of the Salus valve successfully.One valve migrated and was embolized during recovery of the delivery device;the Salus valve was surgically explanted and sutured to the inner wall of the main pulmonary artery.At a mean follow-up of(5.5±1.1)months,dysfunction or migration of the Salus valve embolism was not observed.Conclusions:This early feasibility study demonstrates the feasibility,safety,and effectiveness of transthoracic implantation of a Salus valve in patients with moderate-to-severe PR after NRVOT reconstruction.The short-term effectiveness is clear,medium and long-term effectiveness requires longer follow-up.

可见光驱动环丙烷的自由基开环反应

“环丙烷的结构与反应性质”作为环烷烃章节的重要组成部分,是本科有机化学教学内容的重点之一。当前教材对于环丙烷的开环反应仅提及了几类离子型开环加成反应,如与氢气、卤素等。本文结合学科前沿进展,将可见光催化中环丙烷的自由基型开环反应进行归纳介绍,通过选取本科生易于理解的代表性反应实例,让学生补充了解环丙烷的自由基型开环反应。基础知识课堂与前沿化学研究的深度融合,不仅可以有效补充现有教材中的知识盲区,还能将前沿科技成果转化为教学资源,拓展学生的知识面,提高学习兴趣与效率。

Invasive Hemodynamic and Vasoreactivity Testing with Inhaled Iloprost in Children with Pulmonary Arterial Hypertension Associated with Congenital Heart Defects

Objective:Invasive hemodynamic evaluation and acute vasoreactivity testing are recommended in the diagnosis of pulmonary arterial hypertension(PAH),but their clinical role in children with PAH associated with congenital heart defects(CHD)is unclear.This study aims to investigate acute hemodynamic responses to inhaled iloprost,and its role in prognosis in children with PAH-CHD.Methods:A retrospective analysis was conducted on 83 pediatric patients with PAH-CHD in whom invasive hemodynamics were evaluated before and after a single inhaled dose of iloprost at a single center between 2010 and 2022.Details of the CHD corrective operation,medical treatment,and outcome for each patient were obtained via medical records or telephone contact.A composite endpoint of all-cause death,admission for worsening heart failure during follow-up,and event-free survival was defined,and risk factors associated with this composite endpoint were analyzed.Results:The patient age was(11.3±4.6)years,and 60(72.3%)were female.Fifty-nine(71.1%)patients were diagnosed with Eisenmenger syndrome.After iloprost inhalation,mean pulmonary artery pressure decreased from(78.2±11.5)to(72.3±13.2)mmHg(P<0.001),and pulmonary vascular resistance index(PVRI)decreased from(18.0±7.9)to(14.5±8.1)WU·m^(2)(P<0.001).A total of 38(45.8%)patients had a positive response,defined as a PVRl decrease>25%with stable systemic pressure.Thirtyseven(44.6%)patients underwent a corrective CHD operation at a median of 24 d after hemodynamic evaluation.Nine patients died,and 15 met the composite endpoint during a follow-up period of 5.4(3.8,8.8)years.Five-year event-free survival estimates were 96.7%(95%confidence interval:90.3%-100%)in patients with a positive response,and 82.8%(95%confidence interval:71.7%-94.5%)in patients with a non-positive response(log-rank P=0.012).A positive PVRl response and higher pulmonary arterial oxygen saturation after iloprost inhalation,lower baseline brain natriuretic peptide,and PAH-targeted therapy at follow-up were significantly associated with a favorable clinical outcome.A positive acute vasoreactivity testing response and PAH-targeted therapy at follow-up were independent predictors of outcome in multivariate Cox analysis.conclusions:Acute inhalation of iloprost can lead to a significant decrease in hemodynamic parameters.Responsiveness to inhaled iloprost is associated with better outcomes and can be a valuable predictor of outcomes.