葡萄花色苷的生物合成

文章介绍葡萄花色苷的生物合成途径,及与其相关酶的种类、结构基因和调节基因的研究进展,并对今后这一领域需要进一步研究的问题作了展望。     

马铃薯愈伤组织中色素含量与4个花色苷合成相关基因的表达差异

关基因表达分析发现,绿色和白色愈伤组织不合成花色苷可能与DFR基因不表达有关.本实验结果为进一步阐明花色苷生物合成机理和花色苷色素的生产应用提供一定的理论依据.     

花青素生物合成关键酶的研究进展

花青素是植物花呈现不同色彩的物质基础,其生物合成途径主要受到查尔酮合成酶(CHS)、查尔酮异构酶(CHI)、黄烷酮3-羟化酶(F3H)、类黄酮3'-羟化酶(F3'H)、类黄酮3’,5’-羟化酶(F3'5'H)、二羟基黄酮醇还原酶(DFR)、花色素苷合成酶(ANS)以及类黄酮3-O-糖基转移酶(UFGT)等关键酶的控制.主要介绍花青苷生物合成途径、关键酶晶体结构及利用基因工程改造花色的研究进展,讨论目前花色改造存在的问题,并对今后的研究前景进行展望.     

红景天苷生物、化学和生物催化合成的分子理论及应用

红景天苷是红景天属植物的主要活性成分之一,研究红景天苷的高效合成具有重要的科研和应用价值。本文全面概述近年来合成红景天苷的研究状况,主要包括生物合成途径、化学合成途径、生物催化合成途径。对生物合成途径中红景天苷的代谢合成途径、关键酶及基因、实践现状进行了分析;总结了以Koenigs-Knorr法为理论基础的化学合成的研究进展;对具有广泛发展前景的体外生物催化合成状况进行了理论与实践的概述。通过对这些合成方法的展望,为人们了解合成红景天苷的研究现状、进一步深入研究提供参考。     

花色改变的分子机理研究

自1987年世界首例成功运用转基因技术改造矮牵牛花色以来,花色改造基因工程技术不断展现它在培育新花色品系上的无穷魅力。综述了观赏植物花色素的种类、花色素苷的生物合成途径;关键酶的种类;基因工程改变花色的原理和策略以及花色改良方面的研究进展。     

R2R3-MYB调控果实花色苷合成的研究进展

果皮颜色是决定果实品质和商品价值的重要因子之一,R2R3-MYB转录因子对花色苷的生物合成起着重要的调控作用。本综述从R2R3-MYB转录因子对花色苷合成的正负调控作用,特异性及与其它因子共同调控的花色苷合成网络等方面,介绍了近年来国内外R2R3-MYB在果树上调控花色苷合成的研究。并对今后果树上果实着色的研究作了展望,旨在为进一步开展本领域研究提供相关依据。     

马缨杜鹃Rd3GT1的克隆及对矮牵牛花色形成的影响北大核心CSCD

类黄酮3-O-糖基转移酶(3GT)是花色素苷生物合成途径末端的酶,负责将糖基供体转移至花青素的3-OH位置,在增加花色素苷的稳定性与水溶性方面发挥重要作用。研究马缨杜鹃3GT在花色素苷生物合成中的功能,为马缨杜鹃花色形成及调控研究奠定基础。运用 RT-PCR 技术克隆获得马缨杜鹃3GT基因(Rd3GT1)全长CDS序列,并对其进行生物信息学分析,再利用DNA重组技术完成植物表达载体pBI121-Rd3GT1的构建,利用农杆菌介导法对矮牵牛进行遗传转化,同时对再生植株进行转基因及表型鉴定,并完成基因表达量及花色素苷检测分析。结果表明,Rd3GT1全长CDS序列为1 395 bp,编码464个氨基酸。蛋白多序列比对和系统进化分析表明,Rd3GT1属于3GT家族成员。与野生型相比,转Rd3GT1的矮牵牛植株花色由白色变为粉色,花色素苷与黄酮醇的积累显著增加,同时多个类黄酮合成相关基因表达显著升高。综上,Rd3GT1在花色素苷合成过程中发挥重要功能,可用于其它植物花色改良研究。     

高等植物二氢黄酮醇4-还原酶基因研究进展

花青素苷是影响植物花瓣呈色的重要色素,而花色是决定花卉观赏价值和商业价值的一个重要因素。在花青素苷的生物合成过程中,二氢黄酮醇4-还原酶（DFR）是花青素苷生物合成下游途径中的第一个关键的酶。因此,DFR在高等植物花色的形成过程中发挥极其重要的作用,是形成花青素苷的一个非常重要的调控点。DFR对3种二氢黄酮醇底物具有选择特异性,但决定DFR底物特异性的分子机制目前仍不十分清楚。该文简单概述了花青素苷生物合成途径及其转录调控机制,并结合作者的工作重点综述了DFR的底物特异性以及克隆的DFR基因在植物基因工程中的应用。     

高等植物花色苷的液泡摄取机制

综述了高等植物细胞中花色苷被液泡摄取的机制。花色苷通过细胞质中定位于粗糙内质网细胞质面的多酶复合体合成后被膜包裹形成囊泡。这些囊泡主要向液泡移动,在移动中相互融合形成更大囊泡,最终将花色苷带到液泡膜的表面。在大多数情况下,花色苷经过液泡膜上的各种载体被迅速运进液泡。另外两种较少的是:(1)囊泡直接与液泡融合;(2)液泡膜自主形成大的管状内陷,使囊泡在内陷处指向液泡内腔"发芽"。在上述种种可能的具体过程中,花色苷以非修饰或修饰两种形式被摄入液泡。花色苷跨液泡膜运送可能通过4种模型实现,即由ATP结合盒型的载体介导、由依赖pH梯度的载体介导、由24-kD液泡蛋白前体衍生的蛋白质介导和由多重药物和有毒化合物排出家族的载体介导。据推测,不同植物利用不同的摄取机制将花色苷积累在液泡中,而多重机制也可能被单个植物种同时使用。     

葡萄果实成熟期花色苷与白藜芦醇合成相关基因的表达

以酿酒葡萄‘赤霞珠’为试材,采用pH示差法和高效液相色谱(HPLC)法分别测定葡萄成熟期果皮花色苷和白藜芦醇含量,用实时荧光定量PCR检测两者合成途径中相关基因的表达量,分析花色苷含量和白藜芦醇含量与其相关基因表达的关系,以揭示结构基因与调控基因的调控机制,为筛选富含花色苷和白藜芦醇的酿酒葡萄提供理论依据。结果显示:(1)葡萄果皮花色苷含量在花后112d达到最高值(0.77mg/g),反式白藜芦醇含量在花后126d达到最高值(30.87μg/g)。(2)花色苷和白藜芦醇合成途径中,CHSs、CHI、STS、UFGT、MybA1、MybA2基因的表达量除花后98d下调外,其余时间均呈上调表达,而Myb5a则始终呈上调表达。(3)相关分析表明,STS基因表达量与CHS1、CHS2基因表达量呈极显著和显著正相关关系,MybA1、MybA2基因表达量与CHSs、CHI、STS、UFGT基因的表达量呈极显著正相关关系;Myb5a基因表达量与CHS3基因表达量呈极显著正相关关系。研究表明,部分结构基因的表达与花色苷和白藜芦醇的变化不同步,MybA1和MybA2可能调控花色苷合成途径中多个结构基因的表达,花色苷与白藜芦醇的关系并不固定,而是处在动态变化中。     

Antibiotics in the treatment of wounds in the victims of the earthquake in the Armenian SSR

Purulent wounds in 88 victims of the Armenian earthquake with the syndrome of long-term squeezing were examined microbiologically and the experience with using antimicrobial drugs for their treatment was analyzed. In all the cases microbial associations were detected, coliform and nonfermenting gram-negative bacilli, enterococci, anaerobes and yeast-like fungi being isolated from 80, 20, 15 and 25 per cent of the patients respectively. 130 bacterial strains were studied in detail. 80 to 100 per cent of the bacterial isolates were resistant to the antibiotics routinely used in surgical practice, i.e. benzylpenicillin, tetracycline, levomycetin, kanamycin, cephalothin and cefazolin and highly sensitive to new antimicrobial drugs belonging to ureidopenicillins (mezlocillin), quinolones (ciprofloxacin) and cephalosporins of the 3rd generation (cefoperazone and ceftazidime). Retrospective estimation of the antibiotic therapy revealed its inadequacy in 55.7 per cent of the patients for the most part because of the isolates resistance. The 19 variants of the antibiotic use prescribed by the physicians mainly included penicillins, aminoglycosides and their combinations (in 67.2 per cent of the cases). The use of the highly efficient drugs of the groups of ureidopenicillins and quinolones was extremely rare which was likely due to lacking of information on the drugs.     

Changes in the size of the nucleoli of the Purkinje cells in the canine cerebellum in the postresuscitation period

The changes in the size of Purkinje cell (PC) nucleolus in the lateral and medial cerebellum zones were studied in dogs with different degree of neurologic status recovery after clinical death of various etiology and duration. PC always possess one nucleolus in the control and experimental groups. In the case of complete neurologic status recovery of animals the area of PC nucleolus increases in both zones studied, irrespective of the cause of clinical death. In the case of neurologic disorders the increase in PC nucleolus area is clearly expressed only in the medial zone of the cerebellum, being insignificant in the lateral zone. It is suggested that adaptive characteristics of PC are distinct in the two compared zones, which leads to greater PC vulnerability in the lateral zone during deep hypoxia.     

实物模型在新课程生物中的应用

在实施素质教育的今天,实物模型是新课程生物学教学中极重要的教学工具。因为它能调动学生学习积极性,引导学生主动参与教学活动,对培养学生的学习兴趣和实践能力提高有重要的意义。     

On the role of the pineal in thermoregulation in the pigeon

Diurnal rhythm in body temperature of pigeons subjected to different experimental conditions (pinealectomized, sham-operated, melatonin-implanted, cold-exposed) was studied under a 12 h light and 12 h dark regimen. The body temperature of pigeons during photophase was higher than that during scotophase in the normal as well as every treatment group studied. Pinealectomized pigeons showed higher body temperature in the photophase as well as scotophase, than that of the normal and sham-operated birds when examined 2 or 3 weeks following the post-surgical acclimatization to 25 or 3 degrees C. However, subcutaneous implantation of melatonin pellets into pinealectomized pigeons nullified or even reversed the hyperthermic effect of pinealectomy. Exposure of pigeons to--18 degrees C for 280 min during photophase as well as scotophase, produced a marked drop in body temperature in pinealectomized, sham-operated and normal pigeons. The pinealectomized pigeons exhibited a higher body temperature than that of the sham-operated and normal ones when exposed to--18 degrees C during the photophase, but not during the scotophase. It was concluded that while the pineal is not necessary for maintaining the daily thermal rhythm in the avian body, it has a thermoregulatory role, in that it prevents rise in body temperature in warm (25 degrees C) acclimatized and chronic cold (3 degrees C) exposed birds. In acute short-term cold (--18 degrees C) exposure however, the temperature regulatory role of the pineal was not effective during the scotophase.     

Histogenesis of the taste buds of the vallate papilla in the in the rat in the postnatal stages of development

The developing taste buds of vallate papillae were studied with electron microscope in rats during the first 7 days after birth. Two types of cells--light and dark--are identified in the taste buds of a one day old animal. The apical parts of dark cells are characterized by numerous dark granules. A distinguishing feature of light cells is the presence of synaptic contacts with afferent intragemmal nerves. On the 4th day of development on the top of the apical parts of the cell, a microvillar apparatus is seen to form, which does not yet communicate with the oral cavity. On the 7th day, basal cells appear in the taste buds. Some of these cells are seen mitotically dividing. The differentiated microvillar apparatus now communicates with oral cavity. The structure of the taste buds is getting similar to that in the adults. The structural and functional peculiarities of the developing taste buds are discussed in association with the period of ontogenesis under consideration.     

Diapause termination in the olive psyllid Euphyllura phillyreae, in the field and in the laboratory

Euphyllura phillyreae Foerster (Homoptera: Aphalaridae) which infests olive trees in Greece, is monovoltine and has an aestival-autumnal-hibernal reproductive dormancy as an adult which starts in June. Adult females collected periodically from June through February were maintained for 4 weeks at 12L:12D and 20° L:18° D, then the stage of ovarian development was recorded.In the field, diapause was terminated between mid December and early January. Subsequently, the insects remain in reproductive quiescence until February or early March when environmental conditions allow ovarian development and reproduction.In females collected in June, summerlike laboratory conditions, followed by winterlike, and then by springlike conditions were effective for diapause termination. Springlike conditions alone, or preceded by only summerlike or only by winterlike conditions were not effective. In females collected in August the requirement for summerlike conditions was much less or nil.

---

Résumé Euphyllura phillyreae Foerster qui s'attaque sur l'olivier en Grèce, est une espèce oligophage, monovoltine, qui a une dormance reproductive aestivo-autumno-hivernale au stade adulte, qui commence en juin.Des femelles adultes ont été ramassées par les arbres périodiquement de juin au février et maintenues pendant 4 semaines à 12L:12D et 20° L:18° D. Après cette période, le stade du développement des ovaires a été le critère de la termination de leur diapause. La diapause fut considéré comme terminée quand au moins 50% des femelles avaient leurs ovaires au stade III ou même plus avancées.La diapause fut terminé entre mi-decembre et début janvier. En suite, les insectes restent à une quiescence reproductive jusqu'au février ou début de mars, lorsque les conditions environmentales permettent le développement des ovaires et la reproduction.Des femelles ramassées en juin et en août ont été soumises à certaines conditions de photopériode et de temperature en laboratoire, pour faire terminer leur diapause. Pour celles ramassées en juin, qui étaient au commencement de leur diapause, des conditions semblables à l'été, suivies par des conditions semblables à l'hiver et puis par des conditions semblables au printemps furent effectives pour la termination de la diapause. Seules des conditions semblables au printemps, ou précédées par des conditions semblables seulement à l'été, ou seulement à l'hiver, ne furent pas effectives. Pour les femelles ramassées en août, le besoin pour des conditions semblables à l'été fut beaucoup moin ou nul.