Na_(2)CO_(3)、NaHCO_(3)与稀盐酸反应实验装置的新设计

针对教材中Na_(2)CO_(3)、NaHCO_(3)与稀盐酸的反应装置的不足之处,利用一次性注射器、具支试管、小气球等对实验装置进行了改进。新设计的实验装置简约,易于安装,可操作性强,完善了实验方法,解决了原实验存在的一些问题,有助于提高教学质量。

水杨酸对NaHCO_(3)胁迫下黄芪幼苗生长及生理特性的调节效应

【目的】探究外源水杨酸(SA)缓解盐碱胁迫黄芪种子萌发及幼苗生长生理特性的效应。【方法】以蒙古黄芪为供试材料,利用100 mmol/L的NaHCO_(3)溶液模拟盐碱胁迫,分别设置0.1,0.2,0.3,0.4,0.5 mmol/L外源SA对黄芪种子萌发、幼苗生长进行调节,并以未加SA无NaHCO_(3)胁迫处理为对照1(CK1),未加SA及NaHCO_(3)胁迫为对照2(CK_(2)),测定蒙古黄芪种子萌发指标、幼苗生长及生理指标。【结果】NaHCO_(3)胁迫下(CK_(2))黄芪种子萌发、幼苗生长及生理受到明显抑制,与CK1相比,黄芪种子发芽率、发芽势、发芽指数和活力指数分别降低93.96%、93.45%、97.26%、97.50%,幼苗株高、单株鲜重、根系活力分别降低35.97%、37.61%、72.65%;超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性及可溶性蛋白、脯氨酸(Pro)受到不同程度的抑制,叶片质膜透性、丙二醛(MDA)含量显著增加;与CK_(2)相比,添加不同浓度外源SA后蒙古黄芪种子萌发及幼苗生长显著提高(P<0.05),叶片质膜透性及膜脂过氧化产物MDA含量分别降低了40.21%~56.56%、20.09%~46.39%,抗氧化酶SOD、POD、CAT活性及根系活力得到不同程度增强,渗透调节物质游离脯氨酸、可溶性蛋白积累量显著提高了7.63%~86.95%、5.51%~41.75%。【结论】外源SA可以有效调节NaHCO_(3)胁迫对黄芪种子萌发及幼苗生长的抑制,缓解渗透压并降低膜脂过氧化对黄芪幼苗带来的损伤,增强黄芪种子及幼苗对盐碱胁迫的适应性及抗盐碱能力,其以0.3 mmol/L缓解效果最佳。

工业大麻miR156基因家族在NaHCO_(3)胁迫下的表达模式及生物信息学分析

工业大麻miR156基因家族在碱性盐胁迫响应过程中发挥重要的调控作用,为探究工业大麻miR156基因家族响应NaHCO_(3)胁迫的分子机制,以盐碱耐受型工业大麻品种火麻一号为供试材料,利用生物信息学和qRT-PCR方法,对miR156基因家族进行分析。结果表明,工业大麻miR156家族基因与芦笋、野草莓、苹果和大豆的亲缘关系较近。2条工业大麻pre-miR156序列,产生一条相同的miR156成熟体,且成熟体的保守性较高。在NaHCO_(3)胁迫后的24 h内,工业大麻miR156基因表达量随胁迫时间的延长呈先升高后降低再升高的趋势。该结果为进一步研究工业大麻miR156基因家族及其靶基因的调控网络提供理论依据。

NaHCO_(3)前处理对生物炭性质及其磷吸附能力的影响

为探究NaHCO_(3)前处理对不同种类生物炭性质及其磷吸附能力的影响,借助元素分析、光电子能谱、孔径分析、扫描电镜等手段对比处理前后秸秆、壳核及其他3类生物炭表面特性和孔结构的差异,基于吸附等温线和Freundlich与Dubinin-Radushkevich模型拟合,探讨生物炭性质控制磷吸附的机理。结果表明:NaHCO_(3)前处理总体提高了各类生物炭的比表面积和孔体积,增幅分别为2.70%~110.84%和1.42%~123.80%,提高其芳香性(C C),H/C增幅为5.56%~29.41%,同时降低了极性官能团(C O和C O)含量,极性指数[(O+N)/C]降幅为13.18%~46.34%。原始生物炭的磷释放量范围为78.33~568.33 mg·kg^(-1),NaHCO_(3)前处理显著增加各类生物炭对磷的吸附,使其表现出近似的磷吸附能力(Freundlich吸附系数KF范围为119~254 mg^(1-n)·L^(n)·kg^(-1)),且以物理吸附为主(吸附自由能范围为5.85~7.29 kJ·mol^(-1))。生物炭表面特性对其磷吸附能力的影响大于孔结构,其中C O官能团含量是关键因素。研究表明,NaHCO_(3)前处理通过温和地改变生物炭性质,显著提高其磷吸附能力,是生物炭环境应用的另一种预处理方法。

NaHCO_(3)胁迫下马铃薯根系代谢组差异分析

【目的】分析马铃薯根系对NaHCO_(3)胁迫的代谢组学差异,揭示不同马铃薯品种响应NaHCO_(3)胁迫的代谢分子机制,为优化马铃薯育种、栽培技术措施以及生产应用提供理论依据。【方法】以马铃薯‘V_(7)’和‘康尼贝克’2个品种幼苗根系为研究对象,选用不同浓度梯度(CK、10 mmol/L、20 mmol/L、30 mmol/L、40 mmol/L、50 mmol/L)NaHCO_(3)溶液模拟碱胁迫,胁迫7 d后,结合非靶向代谢组学检测方法,用高效液相色谱(LC-MS)技术及多维统计学对2个马铃薯品种根系代谢产物进行检测分析。【结果】(1)NaHCO_(3)胁迫下,‘V_(7)’根系中检测到160种代谢物上调、91种代谢物下调,‘康尼贝克’根系中125种代谢物上调、52种代谢物下调。(2)2个品种各筛选出10条差异代谢通路,其中植物次生代谢产物的生物合成、不饱和脂肪酸的生物合成、由组氨酸和嘌呤衍生的生物碱合成以及嘧啶代谢这4条差异代谢通路是马铃薯根系响应碱胁迫的关键代谢途径。(3)糖类、酰胺类化合物、胺类、含氧有机化合物、生物碱、酚酸类、菑体-皂苷元等差异代谢物均参与到了马铃薯响应NaHCO_(3)胁迫的复杂调控网络中。【结论】筛选出马铃薯根系响应NaHCO_(3)胁迫的关键代谢产物以及代谢途径,耐碱性品种‘V_(7)’与碱敏感性品种‘康尼贝克’二者根系代谢组学存在差异性;同时,同一个品种不同胁迫程度下其根系代谢与CK也存在差异性。氨基酸及其衍生物、有机酸、尿囊素这3类差异代谢物含量的积累是‘V_(7)’根系代谢过程活跃、耐碱性能力强于‘康尼贝克’的重要特征分子。

不同品种马铃薯幼苗对NaHCO_(3)胁迫的响应及耐碱能力指标筛选

[目的]探究不同马铃薯品种对NaHCO_(3)胁迫的响应机制,为选育耐碱性较强的马铃薯品种提供理论依据。[方法]以V_(7)、后旗红、克新1号、兴佳2号、荷兰15号、康尼贝克6个品种马铃薯为研究对象,以1/2霍格兰(Hoagland)营养液为母液进行了水培试验。营养液设置6个NaHCO_(3)浓度,分别为0、10、20、30、40、50 mmol/L,选择出苗后7天的马铃薯幼苗,缓苗3天后进行碱胁迫处理。胁迫处理7天后,调查马铃薯幼苗株高、茎粗、主根长,分析叶片含氮量和叶绿素相对含量,分析根系脯氨酸含量、过氧化物酶(POD)活性、过氧化物歧化酶(SOD)活性以及过氧化氢酶(CAT)活性等11项生理指标。[结果]随着碱胁迫浓度的增加,各品种马铃薯幼苗生长受到不同程度的影响,在碱浓度30、40、50 mmol/L胁迫处理下,V_(7)根长较0 mmol/L处理分别增加了54.37%、46.04%、25.58%,其余5个品种根长均显著低于0 mmol/L。50 mmol/L胁迫处理下,各品种株高、茎粗均显著低于碱浓度0 mmol/L处理。各品种叶片含氮量、叶绿素相对含量随胁迫浓度增加呈现不同的变化趋势,V_(7)、后旗红、克新1号叶片含氮量均在40 mmol/L处理下达到峰值,兴佳2号叶绿素相对含量在50mmol/L处理下达到峰值,而荷兰15号、康尼贝克叶片含氮量、叶绿素相对含量均在50mmol/L处理达到最小值。各品种幼苗根系活力呈先增后降的趋势,碱浓度40 mmol/L胁迫处理下,V_(7)、后旗红根系活力显著高于0mmol/L,而荷兰15号的降幅达80%以上。各品种幼苗根系中丙二醛含量随胁迫程度加剧而增加,但V_(7)的丙二醛含量始终低于其他品种。各品种幼苗根系CAT活性、SOD活性均呈先升后降变化趋势,其中V_(7)、后旗红、克新1号、兴佳2号的CAT活性、SOD活性高于康尼贝克和荷兰15号。利用主成分分析计算得到5个特征值>1的归一化指标,其对碱胁迫抗性的累积贡献率达80.07%,符合主成分分析要求,因此将11个指标转化为7项生理指标,包括:株高、茎粗、叶片含氮量、叶绿素相对含量、脯氨酸含量、POD活性、CAT活性。[结论]株高、茎粗、叶片含氮量、叶绿素相对含量、脯氨酸含量、POD活性、CAT活性这7项生理指标可作为马铃薯耐碱性能力强弱的评价指标。综合各项指标筛选出耐碱能力较强的品种为V_(7),后旗红、克新1号、兴佳2号耐碱能力中等,康尼贝克与荷兰15号耐碱性较弱。

NaHCO_(3)干法同步脱除垃圾烟气HCl和SO_(2)实验研究

采用NaHCO_(3)干法脱除垃圾烟气中的酸性污染物,针对复杂烟气组分,实验研究了多种关键因素对脱氯和脱硫的影响。结果表明:NaHCO_(3)干法脱酸受温度影响较小,在130~250℃温度范围内,HCl、SO_(2)脱除效率可分别达到95%、90%;增加反应时间可较显著地提升脱酸性能,综合考虑环保及经济性,在碱酸比为1.1时烟道反应段的停留时间控制在1.25 s以上、选择除尘器设计过滤风速为0.60 m/min左右较为合适;烟气含水率小于15%时,水蒸气对SO_(2)的脱除具有较明显的促进作用;在碱酸比≤1.0时,HCl具有明显的优先反应能力;在碱酸比为1.1时,HCl质量浓度每增加100 mg/m^(3),SO_(2)脱除效率约下降1.1%,SO_(2)排放质量浓度约增加4 mg/m^(3),而HCl脱除效率基本不受SO_(2)质量浓度的影响。

Exosomes derived from microglia overexpressing miR-124-3p alleviate neuronal endoplasmic reticulum stress damage after repetitive mild traumatic brain injury

We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury.However,its impact on neuronal endoplasmic reticulum stress following repetitive mild traumatic brain injury remains unclear.In this study,we first used an HT22 scratch injury model to mimic traumatic brain injury,then co-cultured the HT22 cells with BV2 microglia expressing high levels of miR-124-3p.We found that exosomes containing high levels of miR-124-3p attenuated apoptosis and endoplasmic reticulum stress.Furthermore,luciferase reporter assay analysis confirmed that miR-124-3p bound specifically to the endoplasmic reticulum stress-related protein IRE1α,while an IRE1αfunctional salvage experiment confirmed that miR-124-3p targeted IRE1αand reduced its expression,thereby inhibiting endoplasmic reticulum stress in injured neurons.Finally,we delivered microglia-derived exosomes containing miR-124-3p intranasally to a mouse model of repetitive mild traumatic brain injury and found that endoplasmic reticulum stress and apoptosis levels in hippocampal neurons were significantly reduced.These findings suggest that,after repetitive mild traumatic brain injury,miR-124-3 can be transferred from microglia-derived exosomes to injured neurons,where it exerts a neuroprotective effect by inhibiting endoplasmic reticulum stress.Therefore,microglia-derived exosomes containing miR-124-3p may represent a novel therapeutic strategy for repetitive mild traumatic brain injury.

基于实验和密度泛函理论的NaHCO_(3)吸附SeO_(2)机理研究

本研究通过吸附实验探究了140−220℃下NaHCO_(3)对SeO_(2)的吸附性能,通过一系列表征解析了吸附后样品中硒的总量、价态和形态,结合密度泛函理论计算,探讨了NaHCO_(3)对SeO_(2)的吸附机理。结果表明,NaHCO_(3)对SeO_(2)的吸附性能随温度的升高而增加,在吸附过程中同时发生NaHCO_(3)向Na_(2)CO_(3)的分解反应,分解后产生的Na_(2)CO_(3)吸附活性更强。SeO_(2)吸附过程属于SeO_(2)中Se原子与Na_(2)CO_(3)表面O原子成键的化学吸附,吸附产物以亚硒酸盐为主。

不同浓度NaCl和NaHCO_(3)胁迫对制干辣椒光合特性日变化的影响

【目的】研究不同浓度NaCl和NaHCO_(3)溶液对2种制干辣椒品种红椒王和川椒19号光合特性的影响。【方法】以红椒王和川椒19号为试材,以NaCl和NaHCO_(3)溶液浓度为变量,采用盆栽定量浇灌,测定现蕾时辣椒叶片的净光合速率、蒸腾速率、气孔导度和胞间CO_(2)浓度,利用相关性分析、线性回归分析2种制干辣椒品种光合特性日变化规律。【结果】在栽培基质中分别浇灌50、100、150和200 mmol/L NaCl和NaHCO_(3)溶液后,辣椒叶片受到了NaCl和NaHCO_(3)胁迫而出现了净光合速率、蒸腾速率、气孔导度和胞间CO_(2)浓度降低的变化现象。在200 mmol/L NaCl处理下红椒王日平均净光合速率最低为13.79μmol/(m^(2)·s),川椒19号在200 mmol/L NaHCO_(3)处理下日平均净光合速率最低为16.85μmol/(m^(2)·s)。【结论】NaCl和NaHCO_(3)胁迫对红椒王和川椒19号2种制干辣椒品种的光合特性产生了抑制影响。

衔接蛋白失能同源物2通过抑制NOD样受体热蛋白结构域相关蛋白3对结核性胸膜炎大鼠炎症和氧化应激的影响

目的:探讨衔接蛋白失能同源物2(DAB2)抑制NOD样受体热蛋白结构域相关蛋白3(NLRP3)对结核性胸膜炎大鼠炎症和氧化应激的影响。方法:按照随机数字法将60只SPF级雄性SD大鼠分为四组,每组40只。除正常对照组外,结核性胸膜炎组、DAB2组和pcDNA-NLRP3组进行建模处理,以第2天是否抽出胸腔积液为模型建立成功。正常对照组不注射结核分枝杆菌H37RV悬液,DAB2组建模后第2天静脉注射AAV9-DAB2质粒,每天1次,连续注射7 d,DAB2+pcDNA-NLRP3组在注射AAV9-DAB2质粒500μg/L的同时注射pcDNA-NLRP380μl,正常对照组和结核性胸膜炎组的大鼠尾静脉注射0.9%氯化钠溶液。进行各组呼吸功能指标测定,收集胸腔积液,记录积液量,观察3、5、7 d的胸腔积液粘连性情况,HE染色观察胸膜组织病理学情况,Western blot检测胸膜组织中肿瘤坏死因子-α(TNF-α)、白细胞介素-8(IL-8)、基质金属蛋白酶1(MMP-1)和MMP-9蛋白表达,荧光探针DCFH-DA分析检测活性氧(ROS)的水平。结果:与正常组相比,结核性胸膜炎组的大鼠的胸腔积液和胸膜厚度明显增加,用力肺活量(FVC)、最大呼气流量(PEF)、用力呼气容积(FEV)0.3和FEV0.3/FVC显著降低,TNF-α、IL-8、MMP-1和MMP-9蛋白表达显著升高,基质金属蛋白酶抑制剂(TIMP-1)蛋白表达显著降低,丙二醛(MDA)水平升高,超氧化物歧化酶(SOD)水平降低,ROS累积量明显升高(均P<0.001);与结核性胸膜炎组相比,DAB2组大鼠胸腔积液和胸膜厚度显著降低,FVC、PEF、FEV0.3和FEV0.3/FVC明显升高,DAB2组大鼠胸膜组织中的TNF-α、IL-8、MMP-1和MMP-9蛋白表达明显降低,TIMP-1水平明显升高,MDA水平降低,SOD水平升高,ROS累积量明显降低(均P<0.001);与DAB2组相比,DAB2+pcDNA-NLRP3组大鼠胸腔积液和胸膜厚度明显升高,FVC、PEF、FEV0.3和FEV0.3/FVC明显降低,DAB2+pcDNA-NLRP3组的TNF-α、IL-8、MMP-1和MMP-9蛋白表达明显升高,TIMP-1蛋白表达显著降低,MDA水平明显升高,SOD水平显著降低,ROS累积量显著升高(均P<0.001),各组大鼠在3、5、7 d的胸腔积液粘连性评分比较采用重复测量设计的方差分析,结果显示,不同时间点的胸腔积液粘连性评分比较差异具有统计学意义(均P<0.001);各组胸腔积液粘连性评分比较差异具有统计学意义(均P<0.001);各组胸腔积液粘连性评分变化趋势比较差异有统计学意义(均P<0.001);与模型组相比,DAB2组大鼠的胸膜内和肺间质内血管充血症状减轻,有少量的纤维组织增生,上皮样细胞团以及凝固型坏死也明显减少,淋巴细胞和中性粒细胞浸润也明显减少;与DAB2组相比,DAB2+pcDNA-NLRP3组大鼠的胸膜内和肺间质内血管充血症状加重,出现的纤维组织增生,上皮样细胞团以及凝固型坏死也明显增多,淋巴细胞和中性粒细胞浸润也明显增加。结论:DAB2通过抑制NLRP3的活性促进胸腔积液的吸收,降低胸膜厚度和粘连发生率,降低炎症反应和氧化应激水平,缓解结核性胸膜炎的进展。

Functional analysis of flavanone 3-hydroxylase(F3H)from Dendrobium officinale,which confers abiotic stress tolerance

Flavonoids are important bioactive components in Dendrobium officinale,a medicinal orchid.They are involved in many biological activities,including protecting plants against biotic and abiotic stresses.Research on the key genes related to flavonoid biosynthesis in D.officinale is limited.In this study,one of the key flavonoid biosynthesis genes,flavanone 3-hydroxylase(F3H),was characterized from D.officinale.The open reading frame of DoF3H was 1134 bp long and it encoded a 377-amino acid protein.The DoF3H protein showed considerably high homology with F3H proteins from other plant species and shared a common evolutionary ancestor with other F3Hs.DoF3H transcripts were detected in different organs of adult plants and mainly accumulated in flowers,followed by roots,stems and leaves,a pattern that was similar to the content of flavonoids.Recombinant DoF3H protein,which was localized in the cytosol,could convert naringenin to dihydrokaempferol.The mRNA levels of DoF3H were significantly induced by salt and cold stresses.Furthermore,the heterologous expression of DoF3H in Escherichia coli conferred it higher tolerance to salt and cold stresses.These results provide insight into the molecular function of DoF3H in the biosynthesis of flavonoids,and provide a new application for improvement of abiotic tolerance in D.officinale.

DI-3-n-butylphthalide exerts neuroprotective effects by modulating hypoxia-inducible factor 1-alpha ubiquitination to attenuate oxidative stress-induced apoptosis

DI-3-n-butylphthalide is used to treat mild and moderate acute ischemic stroke.However,the precise underlying mechanism requires further investigation.In this study,we investigated the molecular mechanism of DI-3-n-butylphthalide action by various means.We used hydrogen peroxide to induce injury to PC12cells and RAW264.7 cells to mimic neuronal oxidative stress injury in stroke in vitro and examined the effects of DI-3-n-butylphthalide.We found that DI-3-nbutylphthalide pretreatment markedly inhibited the reduction in viability and reactive oxygen species production in PC12 cells caused by hydrogen peroxide and inhibited cell apoptosis.Furthermore,DI-3-n-butylphthalide pretreatment inhibited the expression of the pro-apoptotic genes Bax and Bnip3.DI-3-nbutylphthalide also promoted ubiquitination and degradation of hypoxia inducible factor 1α,the key transcription factor that regulates Bax and Bnip3 genes.These findings suggest that DI-3-n-butylphthalide exhibits a neuroprotective effect on stroke by promoting hypoxia inducible factor-1α ubiquitination and degradation and inhibiting cell apoptosis.

Exosomal miR-23b from bone marrow mesenchymal stem cells alleviates oxidative stress and pyroptosis after intracerebral hemorrhage

Our previous studies showed that miR-23b was downregulated in patients with intracerebral hemorrhage(ICH). This indicates that miR-23b may be closely related to the patho-physiological mechanism of ICH, but this hypothesis lacks direct evidence. In this study, we established rat models of ICH by injecting collagenase Ⅶ into the right basal ganglia and treating them with an injection of bone marrow mesenchymal stem cell(BMSC)-derived exosomal miR-23b via the tail vein. We found that edema in the rat brain was markedly reduced and rat behaviors were improved after BMSC exosomal miR-23b injection compared with those in the ICH groups. Additionally, exosomal miR-23b was transported to the microglia/macrophages, thereby reducing oxidative stress and pyroptosis after ICH. We also used hemin to mimic ICH conditions in vitro. We found that phosphatase and tensin homolog deleted on chromosome 10(PTEN) was the downstream target gene of miR-23b, and exosomal miR-23b exhibited antioxidant effects by regulating the PTEN/Nrf2 pathway. Moreover, miR-23b reduced PTEN binding to NOD-like receptor family pyrin domain containing 3(NLRP3) and NLRP3 inflammasome activation, thereby decreasing the NLRP3-dependent pyroptosis level. These findings suggest that BMSC-derived exosomal miR-23b exhibits antioxidant effects through inhibiting PTEN and alleviating NLRP3 inflammasome-mediated pyroptosis, thereby promoting neurologic function recovery in rats with ICH.

Genome-wide profiling of histone H3 lysine 27 trimethylation and its modification in response to chilling stress in grapevine leaves

Histone H3 lysine 27 trimethylation(H3K27me3) is a histone modification associated with transcriptional repression. However, insights into the genome-wide pattern of H3K27me3 in grapevines are limited. Here, anti-H3K27 chromatin immunoprecipitation(ChIP), high-throughput sequencing, and transcriptome analysis were performed using leaves of Vitis amurensis. The leaves were treated at 4°C for 2 h and 24 h and used to investigate changes in H3K27me3 under chilling treatment. The results show that H3K27me3 is well-distributed both in gene regions(-50%) and in the intergenic region(-50%) in the grapevine genome(Vitis vinifera ‘Pinot Noir PN40024'). H3K27me3 was found to be localized in8 368 annotated gene regions in all detected samples(leaves at normal temperature and under chilling treatments) and mainly enriched in gene bodies with the adjacent promoter and downstream areas. The short-term chilling treatments(4°C for 2 h) induced 2 793 gains and 305losses in H3K27me3 modification. Subsequently, 97.3% of the alterations were restored to original levels after 24 h treatment. The ChIP-qPCR for five differential peaks showed similar results to the data for ChIP-seq, indicating that the chilling-induced H3K27me3 modification is reliable.Integrative analysis of transcriptome and ChIP-seq results showed that the expression of H3K27me3 target genes was significantly lower than those of non-target genes, indicating transcriptional repression of H3K27me3 in grapevine leaves. Furthermore, histone methylation alterations were detected in 82 genes and were related to either repression or activation of their expression during chilling stress. The findings provide the genome-wide H3K27me3 patterns in grapevines and shed light on uncovering its regulation in chilling stress responses.

Hydrogen-bond mediated and concentrate-dependent NaHCO_(3) crystal morphology in NaHCO3–Na2CO3 aqueous solution: Experiments and computer simulations

Adding Na_(2)CO_(3) to the NaHCO_(3) cooling crystallizer, using the common ion effect to promote crystallization and improve product morphology, is a new process recently proposed in the literature. However, the mechanism of the impact of Na_(2)CO_(3)on the crystal morphology is still indeterminate. In this work, the crystallization of NaHCO_(3)in water and Na_(2)CO_(3)–NaHCO_(3) aqueous solution was investigated by experiments and molecular dynamics simulations(MD). The crystallization results demonstrate that the morphology of NaHCO_(3) crystal changed gradually from needle-like to flake structure with the addition of Na_(2)CO_(3). The simulation results indicate that the layer docking model and the modified attachment energy formula without considering the roughness of crystal surface can obtain the crystal morphology in agreement with the experimental results, but the lower molecules of the crystal layer have to be fixed during MD. Thermodynamic calculation of the NaHCO_(3) crystallization process verifies that the common ion effect from Na^(+)and the ionization equilibrium transformation from CO_(3)^(2-) jointly promote the precipitation of NaHCO_(3) crystal. The radial distribution function analysis indicates that the oxygen atoms of Na_(2)CO_(3) formed strong hydrogen bonds with the hydrogen atoms of the(0 1 1) face, which weakened the hydration of water molecules at the crystal surface, resulting in a significant change in the attachment energy of this crystal surface. In addition, Na+and CO_(3)^(2-) are more likely to accumulate on the(011) face,resulting in the fastest growth rate on this crystal surface, which eventually leads to a change in crystal morphology from needle-like to flake-like.

植物14⁃3⁃3蛋白结构与功能的研究进展

14⁃3⁃3蛋白是一类进化上高度保守的磷酸化识别蛋白,以同源或异源二聚体的形式发挥功能。植物14⁃3⁃3蛋白不但参与调控植物开花、叶绿体发育和移动、气孔开放、种子发育、细胞伸长和分裂等过程,还参与调控植物对环境胁迫的响应,如干旱、盐碱和温度等胁迫响应。目前,已鉴定与植物14⁃3⁃3蛋白互作的蛋白超过300个,说明14⁃3⁃3蛋白在植物生长发育过程中具有重要作用。本文主要总结了近年来植物14⁃3⁃3蛋白的结构及功能方面的研究进展。

3-癸烯-2-酮对马铃薯的抑芽作用机理

为探究3-癸烯-2-酮对马铃薯的抑芽作用,本试验以陇薯7号马铃薯为试验材料,以不做任何抑芽处理为对照,采用0.15 mL·kg^(-1)的3-癸烯-2-酮对萌芽期马铃薯进行熏蒸处理,考察3-癸烯-2-酮处理0~5 d对芽眼部位分生组织和生理指标的影响,并分别对处理后48和72 h的马铃薯样品进行转录组分析。结果表明,3-癸烯-2-酮处理后1~2 d,芽分生组织逐渐坏死,3~4 d完全坏死。与对照相比,3-癸烯-2-酮处理组块茎呼吸速率增加,超氧阴离子(O_(2)^(-)·)、过氧化氢(H_(2)O_(2))含量升高,抗氧化酶活性降低,丙二醛(MDA)和蛋白质羰基含量增加。3-癸烯-2-酮处理使得编码9-LOX基因下调表达,改变了植物激素水平,并使光合作用中叶绿体电子传递系统发生紊乱,从而影响果胶甲酯酶活性,改变细胞壁稳定性,最终引起分生组织细胞在短时间内发生膜质过氧化而抑制马铃薯发芽。在此过程中,谷胱甘肽代谢和苯丙烷生物合成通路对氧化胁迫做出了响应。本研究结果可为进一步探索3-癸烯-2-酮抑制马铃薯发芽的分子机制提供参考。

Residual Stress Distribution of Si_(3)N_(4)/SiC Gradient Material and the Effect of Residual Stress on Material Properties

The Si_(3)N_(4)/SiC gradient material with a gradient composition structure was prepared by a hot pressing sintering.The sinterability,distribution of residual stress and the effect of residual stress on mechanical properties of Si_(3)N_(4)/SiC gradient materials were studied.The research results show that,at 1750℃,Si_(3)N_(4)/SiC gradient materials with different ratios can achieve co-sintering,and the overall relative density of the sample reaches 98.5%.Interestingly,the flexural strength of Si_(3)N_(4)/SiC gradient material is related to its loading surface.The flexural strength of SiC as the loading surface is about 35%higher than that of Si_(3)N_(4)as the loading surface.The analysis of the residual stress of the material in the gradient structure shows that the gradient stress distribution between the two phases is a vital factor affecting the mechanical properties of the material.With the increase of SiC content in the gradient direction,the fracture toughness of each layer of Si_(3)N_(4)/SiC gradient materials gradually decreases.The surface hardness of the pure SiC side is lower than that reported in other literature.

Fang-Xia-Dihuang decoction inhibits breast cancer progression induced by psychological stress via down-regulation of PI3K/AKT and JAK2/STAT3 pathways:An in vivo and a network pharmacology assessment

Background:The development and prognosis of breast cancer are intricately linked to psychological stress.In addition,depression is the most common psychological comorbidity among breast cancer survivors,and reportedly,Fang-Xia-Dihuang decoction(FXDH)can effectively manage depression in such patients.However,its pharmacological and molecular mechanisms remain obscure.Methods:Public databases were used for obtaining active components and related targets.Main active components were further verified by ultra-high-performance liquid chromatography-high-resolution mass spectrometry(UPLC-HRMS).Protein–protein interaction and enrichment analyses were taken to predict potential hub targets and related pathways.Molecule docking was used to understand the interactions between main compounds and hub targets.In addition,an animal model of breast cancer combined with depression was established to evaluate the intervention effect of FXDH and verify the pathways screened by network pharmacology.Results:174 active components of FXDH and 163 intersection targets of FXDH,breast cancer,and depression were identified.Quercetin,methyl ferulate,luteolin,ferulaldehyde,wogonin,and diincarvilone were identified as the principal active components of FXDH.Protein–protein interaction and KEGG enrichment analyses revealed that the phosphoinositide-3-kinase–protein kinase B(PI3K/AKT)and Janus kinase/signal transducer and activator of transcription(JAK2/STAT3)signaling pathways played a crucial role in mediating the efficacy of FXDH for inhibiting breast cancer progression induced by depression.In addition,in vivo experiments revealed that FXDH ameliorated depression-like behavior in mice and inhibited excessive tumor growth in mice with breast cancer and depression.FXDH treatment downregulated the expression of epinephrine,PI3K,AKT,STAT3,and JAK2 compared with the control treatment(p<0.05).Molecular docking verified the relationship between the six primary components of FXDH and the three most important targets,including phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha(PIK3CA),AKT,and STAT3.Conclusion:This study provides a scientific basis to support the clinical application of FXDH for improving depression-like behavior and inhibiting breast cancer progression promoted by chronic stress.The therapeutic effects FXDH may be closely related to the PI3K/AKT and JAK2/STAT3 pathways.This finding helps better understand the regulatory mechanisms underlying the efficacy of FXDH.