杜仲雄花中次生代谢物合成积累的动态变化

对杜仲(Eucommia ulmoides Oliv.)雄株不同花期雄花中次生代谢产物含量进行分析测定,并对杜仲雄花次生代谢的生理基础及不同花期次生代谢产物含量差异进行了探讨.研究结果表明,雄花在不同花期次生代谢产物含量均有差异.总黄酮含量在花蕾期最高(4.010%),始花期最低(2.422%),从盛花期到末花期逐渐上升;桃叶珊瑚苷和绿原酸含量均在花蕾期最高(分别为2.351%和1.075%),盛花期最低(分别为1.463%和0.503%),至末花期含量上升;京尼平苷酸含量在始花期最低(0.217%),从盛花期开始逐渐升高,至末花期高达1.403%;次生代谢产物总量也以花蕾期为最高(7.420%).杜仲雄花的花蕾期和盛花期是兼顾质量和产量的最佳采摘期.     

嘉宝果不同发育期花果叶的挥发性成分分析

为了解嘉宝果(Myrciaria cauliflora)的挥发性成分,利用顶空-气相色谱/质谱联用技术对其不同发育期的花、果、叶的挥发性成分进行测量。结果表明,萜烯类是花、果、叶的主要挥发性成分,随开花进程呈增加趋势,随果实和叶片成熟进程而下降,单萜类是其中的优势成分,主要有α-蒎烯、β-蒎烯、D-柠檬烯、β-罗勒烯等;花苞期、初花期和嫩叶以β-蒎烯含量最高,盛花期和老叶以α-蒎烯最高,末花期和果实中均以D-柠檬烯含量最高,嫩叶中α-蒎烯和β-蒎烯的总含量高达62.07%。酯类在花期中以初花期含量最高(16.92%),在果实中以完熟期含量最高(14.81%),老叶中酯类含量(4.35%)显著高于嫩叶(0.26%)。因此,α-蒎烯和β-蒎烯是花、果、叶共有主香成分,柳酸甲酯和苯乙醇是花苞期和初花期特征主香成分,毕澄茄烯是完熟果特征风味物质,β-石竹烯是嫩叶特征主香成分,桉叶油醇和β-胡椒烯是老叶特征主香成分。     

不同花期厚朴雌雄蕊和花瓣香气组成成分的分析和比较

采用固相微萃取和GC-MS技术,对初花期、展瓣期、盛花期和盛花末期厚朴(Magnolia officinalis Rehd.et Wils.)雌雄蕊和花瓣香气的组成成分及其相对含量进行了分析和比较.结果表明:不同花期厚朴雌雄蕊和花瓣香气的组成成分及其相对含量差异明显.雌雄蕊和花瓣香气分别含有52和37种成分,总计67种;其中,1-甲氧基-3,7-二甲基-2,6-辛二烯、1-香叶基乙醚、D-柠檬烯、莰烯、月桂烯和石竹烯等成分的相对含量均较高.初花期、展瓣期、盛花期和盛花末期雌雄蕊香气分别含有26、26、27和24种成分,花瓣香气则分别含有22、19、16和21种成分;不同花期雌雄蕊和花瓣香气的共有成分为1-甲氧基-3,7-二甲基-2,6-辛二烯、D-柠檬烯和石竹烯.不同花期厚朴雌雄蕊和花瓣香气成分可分为萜烯类、醇类、芳香烃类、醚类、醛酮类、酯类、烷烃类和含氮类8类,共有类型为萜烯类和醇类,其中,萜烯类是主要组成成分.厚朴雌雄蕊和花瓣在不同花期均释放出较多的萜烯类化合物,其相对含量随着花的发育呈先升高后降低的趋势.根据感官分析与GC-MS分析结果综合判断:萜烯类化合物是组成厚朴花香气的重要成分;花瓣是香气释放的主要部位,而雌雄蕊则在香气释放过程中起辅助作用.     

菊花不同花期及花序不同部位香气成分和挥发研究

以切花菊品种‘神马’为试材,采用顶空-固相微萃取和气相色谱-质谱联用(GC/MS)技术,分别测定菊花不同花期及花序不同部位的香气成分种类和含量,并利用生物显微镜观察花瓣的表皮细胞和横切面组织细胞的结构特征。结果表明:(1)菊花花蕾期共检测到香气成分24种,始花期31种,盛花期43种,终花期22种;随着花朵的开放和凋谢,酮类、萜烯类和醇类化合物的含量呈先上升后下降的趋势,在盛花期含量达到最高,而酯类、醛类和杂环类化合物则呈持续下降的趋势。(2)盛花期,在舌状花中共检测到香气成分种类31种,在管状花中共检测到50种;舌状花对菊花香气的贡献比管状花大;菊花舌状花由内轮向外轮香气成分种类变化不大,但是同类香气成分含量的变化出现由内轮向外轮逐渐减少的趋势。(3)异环柠檬醛、桉叶醇、α-蒎烯、β-金合欢烯和石竹烯等化合物可能为菊花的主要特征香气成分。(4)显微观察结果表明:舌状花的香气可能是通过表皮细胞间隙释放的,上表皮是菊花释放香气的主要部位。     

细茎石斛花朵挥发性成分分析

为了探究细茎石斛花朵释放的挥发性成分特点,该研究利用固相微萃取(SPME)法结合GC-MS技术,检测了花色为黄绿的细茎石斛花朵不同花期、不同部位的挥发性成分和相对含量,还比较了黄绿色、白色和白色带淡紫色等三种花色的挥发性成分。结果表明:花色黄绿的细茎石斛花朵挥发性化合物成分总计为59种,其中盛花期最复杂(含有41种),这些成分归属于烯类、芳香族化合物、含氮化合物、酯类、醇类和醛酮类。在不同花期检测到的挥发性成分中,(1R)-(+)-α蒎烯相对含量始终最高,保持在27%以上;始花期和盛花期释放且相对含量较高的成分有顺-芳樟醇氧化物、β-水芹烯、柠檬烯、罗勒烯、(1S-cis)-4,7-二甲基-1-(1-甲基乙基)-1,2,3,5,6,8α-六氢萘和乙酸芳樟酯,相对含量均高于5%;衣兰烯于花蕾期相对含量最高,衰落期消失。这8种化合物可能是细茎石斛花香释放的主要香气成分或特征成分。在花色黄绿的细茎石斛盛开期的两个开花部位中,花瓣的挥发性成分有27种,蕊柱17种,其中烯类物质分别占74.16%和79.06%,花瓣可能是细茎石斛主要的释香部位。三个花色的细茎石斛盛花期挥发性化合物均在40种左右,既有成分的差异又有含量的差别,其中有25种为共同含有,三个花色均是(1R)-(+)-α蒎烯相对含量最高,含量在27%左右。这表明烯类物质是影响细茎石斛花香的重要化合物,不仅对细茎石斛产品开发提供了参考,而且还为其花香基因工程育种奠定了基础。     

丹桂4个花期挥发性成分GC-MS分析及清除DPPH自由基活性的研究

采用水蒸气蒸馏法提取丹桂花不同时期的挥发油,结合气相色谱-质谱联用技术对其进行分析和鉴定,用面积归一化法测定各组分的相对百分含量,并对该挥发油清除1,1-二苯基-2-三硝基苯肼(DPPH)自由基能力进行了研究。结果表明:丹桂初花期、盛花初期、盛花期和末花期4个时期分别鉴定出29、30、34和27种化学成分,共鉴定出61种化合物,包括萜烯类15种、醇类15种、醛类6种、酮类9种、酯类8种、烷烃类6种、炔烃1种及氧化物类化合物1种,它们共有成分有8种,此外还检测到一些特有成分,初花期14种、盛花初期5种、盛花期5种和末花期4种。丹桂花挥发油具有一定清除DPPH自由基的能力,但其清除能力低于同质量浓度的Vc。     

‘重瓣红’玫瑰不同花发育阶段转录和代谢差异分析

为探究调控‘重瓣红’玫瑰花发育过程中花香关键基因和代谢通路,对花不同发育阶段样本进行转录组和代谢组测序分析。转录组学分析在花蕾期、初开期、半开期、盛开期和落花期对比中分别检测出4 435、2 444、7 021、4 123个差异表达基因,其中5个阶段共有差异基因214个。代谢组学共检测到508个代谢物,230个差异代谢物,在不同发育时期代谢物有明显的差异,代谢物被分为4簇。在分析玫瑰花香苯环类和萜烯类合成途径中,发现差异表达基因58个,差异代谢物11个。结合转录组和代谢组分析,花发育过程基因和挥发物质变化明显,花蕾期形成单萜类物质,半开期挥发物逐渐积累,落花期代谢物释放量减少,典型玫瑰花香物质主要在半开期形成。因此,选择合适采收时间有助于玫瑰花香品质的形成与保留。     

单瓣茉莉花发育过程中香精油成分及含量的变化

为探讨单瓣茉莉(Jasminum sambac‘Unifoliatum’)花发育过程中的香精油成分和含量的变化,采用顶空固相微萃取(HSSPME)和气相色谱-质谱联用(GC-MS)技术进行分析。结果表明,单瓣茉莉花在不同发育时期的香精油成分及含量差异明显,花蕾初期、花蕾成熟期、微开期、盛开期和盛开末期分别鉴定出7、25、27、23和16种化学成分。萜烯类化合物是花蕾初期的主要香精油成分,花蕾成熟期、微开期和盛开期的萜烯类、酯类和醇类化合物的含量均较高,是主要的香精油成分,但化合物种类和含量存在较大差异。盛开末期的主要香精油成分是萜烯类和杂环类化合物。单瓣茉莉鲜花的主要化学成分或前体物质在花蕾成熟期基本形成,大部分芳香成分在微开期的含量最高。因此,生产中提取茉莉花精油或熏茶时,应选择微开期的鲜花进行采摘,但在不能及时窨制花茶或提取香精油的情况下,选择花蕾成熟期的花采摘更为合适。     

‘辣椒95-1’保持系与雄性不育系花蜜腺的发育解剖学研究

采用扫描电镜和石蜡制片技术对'辣椒95-1'雄性不育系和同型保持系的花蜜腺及其发育过程进行了比较研究.结果表明:雄性不育系和同型保持系花蜜腺的位置、形态、结构及发育过程相似.辣椒的花蜜腺位于子房基部,围绕子房,属于子房蜜腺.蜜腺由分泌表皮和泌蜜组织组成.分泌表皮外覆角质膜,表皮无气孔分布,泌蜜组织为多层薄壁细胞.蜜腺由子房基部的外层表皮及其相邻的内侧细胞分裂、生长、分化而来.在花蕾膨大期,蜜腺细胞的细胞质较浓,已经开始积累淀粉粒和蛋白质;露冠期,分泌表皮和泌蜜组织的细胞质稀,淀粉粒和蛋白质大量增加;花蕾初放期,细胞质浓,淀粉和蛋白质的含量都非常高;盛花期,细胞质稀,液泡增大且数量增加,淀粉和蛋白质的量减少;败花期,细胞质稀,形成中央大液泡,淀粉重新积累.     

不同成花量金花茶花果期果枝叶内源激素的变化

该研究运用酶联免疫法(ELISA)对不同成花量(花多、花少、无花)金花茶花果期果枝叶内源激素吲哚乙酸(IAA)、赤霉素(GA_3)、玉米素核苷(ZR)、脱落酸(ABA)含量进行了测定。结果表明:始花期金花茶果枝叶内源IAA先升高后降低,花多株含量低于花少株;有花株ZR含量高于无花株;GA_3含量呈现整体上升趋势,有花株高于无花株;ABA含量先降低后升高,无花株高于花多株。盛花期IAA、GA_3、ABA含量整体下降,ZR含量先降低后升高,花多株叶内源IAA、ZR、GA_3含量高于花少株或无花株,ABA含量低于花少株或无花株。花期内,有花株果枝叶IAA/ZR、IAA/ABA、ZR/ABA、GA_3/ABA比值均高于无花株,而(IAA+GA_3)/ZR比值低于无花株,说明金花茶花果的发育不仅和单个激素的含量有关,还和激素平衡有关。秋梢期营养生长旺盛时无花株IAA/ZR比值较大,花果期生殖生长强烈时比值较小,(IAA+GA_3)/ZR与之相反。这说明花蕾期高水平的内源IAA、ZR和ABA及低水平的内源GA_3有利于金花茶开花;末花期高含量的IAA、ZR和低含量的GA_3、ABA可减少落花落果,提高坐果率,有利于果实快速生长;果实生长后期高含量的ABA有利于果实成熟。该研究结果为生产上应用生长调节剂调控金花茶成花、坐果提供了理论依据。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.