根癌农杆菌介导蓝猪耳转化的影响因素研究

研究了根癌农杆菌介导蓝猪耳转化的影响因子。结果表明,以蓝色花类型蓝猪耳5~6周的叶片为外植体,在OD₆₀₀为0.5~0.6的活化菌液中浸染5~10min,暗培养4d后,在愈伤组织诱导培养基(MS+BA 1.0mg/L+2,4-D 0.1mg/L)上生长14d,获得抗性愈伤组织;经芽诱导培养基(1/2MS+BA 1.0mg/L+NAA 0.1mg/L)培养28d得到抗性芽;生根培养基(1/2MS)上培养14d得到抗性植株。经PCR检测证实外源基因已整合到蓝猪耳基因组中,转化率达13%~14%。Cef和Hyg浓度对转化影响较大,转化的不同阶段其适宜浓度不同。     

电针大鼠的血清中淋巴细胞转化抑制因子的作用机制分析

本室以前的工作表明:电针(2H_z,3V,30min/d)刺激 SD 大鼠双侧足三里-三阴交,5d后,大鼠血清中产生出淋巴细胞转化抑制因子,本工作对此抑制因子的作用机制进行了初步研究,主要结果如下:(1)电针大鼠的血清不仅显著抑制 Con A 刺激的小鼠淋巴结 T 淋巴细胞转化,还可显著抑制 Con A 刺激的小鼠胸腺细胞和脾脏 T 淋巴细胞转化;同时也发现电针大鼠的血清能显著抑制脂多糖(LPS)刺激的小鼠淋巴结 B 淋巴细胞转化。提示此淋巴细胞转化抑制因子对不同淋巴器官及不同类型的淋巴细胞无选择性作用。(2)将电针大鼠的血清同小鼠淋巴结细胞培养1h,电针大鼠的血清就可显著抑制 Con A 刺激的 T 淋巴细胞转化;将小鼠淋巴结细胞同 Con A 预培养30min,电针大鼠的血清的抑制作用便消失,提示电针大鼠血清中淋巴细胞转化抑制因子作用于 Con A 刺激 T 淋巴细胞活化的早期阶段,同时也排除了此抑制因子的细胞毒作用。(3)电针大鼠的血清显著抑制蛋白激酶 C(PKC)激活剂 PMA和 PMA 加 ca~(2+)通道 A23187刺激的小鼠淋巴结细胞转化,提示淋巴细胞转化抑制因子通过抑制 PKC 的活性或抑制 PKC 介导的细胞活化通路,抑制有丝分裂原刺激的淋巴细胞转化。     

转化生长因子—β（TGF—β）的结构

1978年,Delarco和Todar首先发现病毒转化的细胞能分泌一种具有使正常大鼠肾成纤维细胞表型发生转化能力的因子,它在表皮生长因子(EGF)存在的情况下使贴壁生长的细胞特性发生改变,获得在软琼脂培养基上生长形成克隆的能力,并失去生长密度依赖的抑制作用。因此,这种细胞因子被命名为转化生长因子-β(TGF-β)。在过去的10年中,发现TGF-β实际上是一种具有多种生物学功能的细胞因     

适于无血清贴壁培养的抗凋亡宿主细胞系CHO-IVB2的构建

应用无血清培养基培养CHO细胞时,由于没有血清提供各种贴壁因子,细胞以悬浮的方式生长。在实际的大规模细胞培养中,CHO细胞往往以贴壁方式培养,要么贴壁于悬浮的微载体中,要么贴壁于固定的聚酯盘状介质或中空纤维中,而很少直接悬浮于培养基中。在无血清培养基中,Vitronectin单一组分可以促使CHO细胞的贴壁和扩增。通过双表达lgf-1和Bcl-2基因,已经构建了可以在无蛋白培养基IMEM中抗凋亡生长的细胞株CHO-IB3。在此基础上,构建了可以同时表达Igf-1、Vitronectin和Bcl-2三个蛋白的三顺反子表达载体pCI—NII—IVB。将该载体转染于CHO—dhfr^-细胞中,构建了一个细胞株CHO—IVB2。该细胞株可以在无蛋白培养基中抗凋亡生长,适于以贴壁的方式大规模培养,用于大量生产外源目的蛋白。     

绿豆组织培养物的遗传转化

将绿豆(Phaseolus aureas),蚌埠绿豆,vc27784A,安引5—16号等的种子。消毒处理后,接种于1/2MS 培养基上,获无菌苗。然后取三日龄绿豆子叶、下胚轴;八日龄绿豆上胚轴切段、叶片;十五日龄茎的切段与3850-1103,3850-4农杆菌共培养10分钟,洗净吸干,培养在无抑制剂(头孢霉素)的诱导培养基(BA 0.5 IAA 1.0mg)上预培养4天,然后转入含头孢霉素量1000μg/ml 的诱导培养基上,其中3850-4转化的部分组织块移入不含 BA 的诱导培养     

F9胚胎癌细胞的转化生长因子及其免疫细胞化学定位

恶性肿瘤细胞的特性之一是在血清浓度较低的培液中也能照常增殖。1978年DeLarco和Todaro首先在小鼠肉瘤病毒转化细胞的条件培液中找到了一种转化生长因子(Trans-forming Growth Factor简称TGF),它具有(1)使正常细胞在体外生长中的接触抑制现象消失和(2)使它们的形态发生变化,并获得了锚着不依赖(anchorage independent)生长的特性。随后,他们假设肿瘤细胞自己分泌生长因子是它们对外源生长因子的需求量减少的原因。几年来不仅从很多种病毒和化学物转化的癌细胞和人类肿瘤细胞中,还在胚胎细胞,甚至正常成年组织中分离得到了多肽生长因     

沙打旺悬浮培养细胞原生质体的体细胞胚胎发生再生植株(英文)

以继代培养5—24代的沙打旺(Astra-galus adsurgens Pall.)胚性悬浮系为材料,从生长4d的细胞培养物中可游离出大量有活力的原生质体。细胞预质壁分离或低温预处理对原生质体得率和活力没有影响,但可提高原生质体培养的植板率。预处理的原生质体培养在NH_4NO_3浓度降至2.5mmol/L,并附加0.5mg/L NAA、1.0mg/L 2,4-D、0.7mg/L BA和0.4mol/L葡萄糖的KM8P培养基中,经持续分裂形成细胞克隆,植板率高达16%—20%。细胞克隆在附加1.0mg/L 2,4-D和0.5mg/L BA的MS培养基中增殖后,转至含0.1mg/L NAA和1.0mg/L BA的MS分化培养基中可形成体细胞胚,平均体细胞胚发生频率约为40%,每个克隆产生20—40个体细胞胚。在无激素的1/2MS培养基中,体细胞胚发育成形态正常和染色体数稳定的小植株。     

诸葛菜(Orychopheagmus violaceus)叶肉原生质体培养再生植株

由诸葛菜无菌苗的叶肉组织分离原生质体,在附加0.5 mg/L BA,1.0 mg/L 2,4—D(或NAA)和9％甘露醇的MS液体培养基中作浅层培养,10d后分裂频率约45％,两周时形成大量细胞团,随后直接转到分化培养基上或逐步降低原生质体培养基的渗透压及生长素浓度,均可诱导形成大量苗或胚状体结构。转移到无激素的培养基上即可形成完整植株。     

苗龄与红光对向日葵原生质体分离和培养的影响

用1.0—1.5%(W/V)纤维素酶(Onozuka R-10)和0.3—0.5%(W/V)果胶酶[Pectinasc (Serva)]配合分离到大量有活力的向日葵下胚轴原生质体,经液体浅层培养或琼脂糖小块培养7—10天后,均能持续分裂到细胞团或体细胞胚,至14—21天形成大量肉眼可见的小愈伤组织(直径0.5—2.0mm)。比较试验表明:(1)影响向日葵下胚轴原生质体分裂生长的首要因素是起始材料无菌苗的生理状态。用红光照射无菌苗,能明显地促使下胚轴原生质体在较低密度(1×10~4/ml)培养时,也能持续分裂,再生小愈伤组织;(2)在MS培养基上添加5mmol/L谷氨酰胺或以7.5mmol/L谷氨酰胺代替原培养基中的无机氮,能促使原生质体高频率(44.4%左右)分裂,再生愈伤组织。     

发根土壤杆菌体外转化甘草子叶及下胚轴

利用发根土壤杆菌农杆碱型15834、A_4菌株和甘露碱型8196、K_(599)菌株体外转化甘草子叶及下胚轴。结果表明:除K_(599)菌株外,其余三种菌株都能诱导产生甘草发状根无性系。其中15834菌株的诱导率最高,下胚轴的诱导率高于子叶。组织学观察表明,在感染后4天左右,下胚轴维管束鞘外细胞、特别是形成层部分细胞大量启动形成分生细胞及分生细胞团,并进一步分裂形成根原基。6—8天后根原基具单向极性生长形成完整的发状根结构。发状根能在无外源激素的培养基上迅速生长。高压纸电泳检测到发状根中存在农杆碱及甘露碱,说明Ri质粒T-DNA编码的这两种冠瘿碱合成酶基因在甘草细胞中得到了表达。     

Activity of synthetic gibberellin A15 and (±)-gibberellin A15isolactone

The activities of (±)-gibberellin A₁₅ ((±)-GA₁₅) and (±)-gibberellin A₁₅-isolactone ((±)-iso-GA₁₅) which were obtained by stereocontrolled total synthesis and gibberellin A₁₅ (E-GA₁₅) synthesized by interconversion of enmein were assayed by the rice seedling test. As expected, (±)-GA₁₅ showed half the activity of natural gibberellin A₁₅ (GA₁₅). E-GA₁₅ which has a natural configuration showed the same activity as natural gibberellin A₁₅ while (±)-iso-GA₁₅ was almost inactive. These samples were also submitted to the cucumber hypocotyl assay. Contrary to what has already been reported, they were almost inactive.     

类整合素在烟草花粉萌发和花粉管生长中的作用

本文研究了动物整合素VnR抗血清及动物整合素专一性抑制剂含RGD的多肽对体外及半体内培养条件下烟草花粉萌发及花粉管生长的影响。结果表明在体外培养条件下,VnR抗血清及GRGDSP肽对花粉的萌发及花粉管的生长没有明显的抑制作用,但可抑制钙调素促进的花粉萌发和花粉管的生长;两者对柱头上进行的花粉萌发及在花柱里进行的花粉管生长也有一定程度的抑制。对类整合素在花粉萌发及花粉管生长中的作用进行了讨论。     

成纤维细胞表皮生长因子的胞吞和向细胞核转移研究

本文以C3H小鼠胚胎正常成纤维细胞株C3H10T1/2C18(简称NC3H10)及其由氚标记脱氧胸苷(~3H-TdR)恶性转化的细胞株(简称TC 3H 10)为对象,研究了表皮生长因子(EGF)在受体介导下的胞吞和向细胞核转移现象。~(125)I-EGF 与细胞膜上的EGF 受体结合后,胞吞和向细胞核转移呈时间依赖性。两种细胞的EGF 的胞吞和向细胞核转移率接近。但是NC 3 H 10细胞~(125)I-EGF 胞知和向细胞核转移的绝对量明显高于TC 3 H 1 0细胞(p<0.05)。SDS-PAGE 电泳表明向细胞核转移的~(125)I-EGF 是未被降解的完整分子,溶酶体抑制剂NH_4Cl 对~(125)I-EGF 向细胞核转移有明显促进作用(p<0.05)。这些结果表明受体介导下的EGF 胞吞和向细胞核转移可能与EGF 的细胞核内凋节作用密切相关。     

Effect of recombinant growth hormone on expression of growth hormone receptor, insulin-like growth factor mRNA and serum level of leptin in growing pigs

Growth hormone (GH) plays an important role in regulation of animal growth, metabolism and lactation[1]. Numerous studies have shown that exogenous somatotropin (ST) can increase average daily weight gain, improve feed efficiency, stimulate protein deposition and muscle growth and decrease lipid accretion rate[1]. The original somatomedin hypothesis suggested that the effect of GH on postnatal growth was mediated by insulin-like growth hormone factor 1 (IGF-I) which was thought to be deriv…     

pH值对萼花臂尾轮虫种群增长及繁殖的影响

采用种群积累培养法,实验观察了 ｐＨ在３．５～１１．５之间（间隔 １）萼花臂尾轮虫 （Ｂｒａｃｈｉｏｎｕｓ ｃａｌｙｃｉｆｌｏｒｕｓ）种群的增长及繁殖．结果表明,该轮虫种群在ＰＨ６．５～８．５之间增 长较快, ８． ５时增长最快,即瞬时增长率 ｒ和种群密度较大和最大; ｐＨ在 ３． ５～４． ５和 ９． ５ ～１０． ５之间,种群为负增长,即 ｒ为负值; ｐＨ在 ５． ５～９． ５之间种群为正增长,即正为正 值．该轮虫存活的ｐＨ上限为１１．５,下限为３．５．在种群增长最适ｐＨ（８．５）条件下,该轮虫 的繁殖最快,即绝对带卵量最高（１３２个·ｍｌ－１）;ｐＨ在９．５时,其相对带卵量最高．为其它 ｐＨ值条件下的２～４倍．本研究结果可为淡水轮虫的大批量培养提供可靠的ｐＨ值技术指 标．     

Postnatal growth of skull linear measurements of Cape Hare Lepus capensis in northern China: an analysis in an adaptive context

304 skulls of Cape hare (Lepus capensis) were collected from two climatically distinct localities in northern China. With eye lens weight as a continuous age variable, postnatal growth patterns of 25 cranial linear measurements in relation to sex, growth season and region were analysed to understand the morphological basis of life history adaptation. In almost all the skull measurements, no significant differences were found between either sex or growth seasons. Principal component analysis revealed that facial elements accounted for the greatest proportion of skull morphological variation. Von Bertalanffy function was applied to describe growth trajectories of the skull elements. Based on this model, the growth rates of skull elements and the age at which they reached a certain proportion (95%) of asymptotes were compared. The results showed that skull growth exhibited an allometric pattern, with neural components attaining their final size more rapidly (at about 2–3 months old in tympanic bulla and 4–6 months old in others) than did the facial, which continued to grow well into postnatal life (at 6–10 months old). The earlier establishment of neurocranial morphology was associated with a fully developed central nervous system, which may play a key role in improving the survival of animals during the early phase of life. There was a regional difference in developmental rate of the hare skull. For all the skull parameters, northern hares had a more rapid rate of cranial growth compared to the southern, i.e. skull elements of juveniles from northern population were relatively larger at comparable ages and achieved adult size 0.5–4.0 months earlier than those from the south. In adult hares, however, no significant regional differences in any of the skull parameters were present. Adaptive explanations for the regional difference in ontogenetic pattern of skull morphology include age‐specific thermoregulation constraint, season‐related food availability and age‐dependent predation pressure. Based on the findings of this study, it is suggested that the postnatal growing period represents a crucial time of life, and that improvement of survivorship when young by growth adaptation forms an important aspect of the hare's life history strategies. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 78 , 343–353.     

培养介质pH和EGTA对水霉(Saprolegnia ferax)菌丝细胞肌动蛋白的分布与结构的影响

菌丝在pH 5.0—8.0介质中维持顶端生长,Rhodamin-phalloidin荧光探针显示在菌丝顶端都存在F-actin的“帽子”结构;加入EGTA到培养介质中不影响菌丝的顶端生长和actin的“帽子”结构。值得注意的是:菌丝的Rhodamin-phalloidin荧光强度大小与菌丝顶端生长速率成正比;在含有或不含有EGTA的pH5.0培养条件下,菌丝的生长速率均很低,且后部颗粒状的荧光斑点消失;在pH 3.0-4.0培养介质中菌丝生长停止,不但F-actin“帽子”结构消失,整个菌丝荧光也变得非常微弱无法观察,提示酸性pH可引起F-actin的解聚,从而导致生长速率下降甚至生长停止。     

Failure to induce over-compensation of growth in maturing yellow perch

Unlike juvenile F1 male bluegill Lepomis macrochrus × female green sunfish L. cyanellus , maximized episodes of compensatory growth (CG) in 2 year yellow perch Perca flavescens did not surpass control masses because internal regulation caused abrupt appetite reduction upon catch-up. Together, the hybrid sunfish study and present work indicate that CG-maximizing feeding schedules and absence of an internal growth limiting mechanism are both required to produce substantial growth overcompensation (GOC). The less vigorous and less resilient CG responses of the yellow perch relative to those of the similarly fed hybrid sunfish appear indicative of the lack of GOC capacity in the former. This contrast, and results of previous studies are interpreted to suggest that GOC capacity may be limited to early life stages of fishes which have a substantial reproductive potential but are at high risk of mortality due to their small size. The possibility that GOC capacity is time-of-year-dependent and species-specific is considered also. Food deprivation periods that produced the strongest CG responses differed for male (2 days) and female (12 days) yellow perch. Among controls fed without restriction, growth rate and growth efficiency of female yellow perch exceeded those of males two-fold, however, males showed a greater capacity to catch-up to same-sex controls when undergoing CG. A feeding schedule using maintenance feeding v. food deprivation to elicit CG yielded the most rapid catch-up to control masses in the yellow perch. Such feeding schedules may produce even greater GOC than was achieved previously in hybrid sunfish, where feeding schedules involving food deprivation were employed.     

逆转录病毒介导人VEGF在兔皮肤成纤维细胞中的表达

本文以人VEGFcDNA为目的基因,构建成逆转录病毒质粒载体,并进一步包装成重组缺陷型逆转录病毒,以此感染原代兔皮肤成纤维细胞,经G418筛选,获得了具有分泌VEGF能力的抗性细胞克隆,经Southern、PCR、Northern、RT-PCR等检测,证实了外源基因已整合至原代兔皮肤成纤维细胞基因组中,无重排和产生野生型病毒之患。整合的VEGF可在修饰细胞中转录,经内皮细胞增殖实验和血管通透性实验证实其表达产物具有强大的生物活性。为进一步研究VEGF的生物学功能和生理效应提供有用的工具。     

黄芫花提取物对V_(79)细胞和WB肝细胞的生物学效应 1.细胞连接通讯与增殖活性的相关性变化

用SLDT技术、细胞生长曲线、~3H-TdR掺入、细胞分裂指数和流式细胞光度术等方法在V_(79)细胞和WB肝细胞中观察到中药促癌物黄芫花提取物刺激细胞增殖的作用与对细胞GJIC抑制的作用有平行相关性。黄芫花提取物抑制V_(79)细胞的GJIC,同时刺激DNA合成,使细胞周期M期时相百分比升高,与TPA的效应相似,对黄芫花提取物促癌作用机理、GJIC抑制与细胞增殖周期的相关性进行分析讨论。