An autonomously propagating luciferase-encoding vector for Dictyostelium discoideum

We have constructed a luc reporter vector for Dictyostelium discoideum using a 626-bp fragment from the nuclear-associated plasmid Ddp2. The ori from Ddp2 is localized within this fragment and was used to provide an autonomous replication sequence for the reporter vector. This reporter vector was stably retained in D. discoideum AX3K cells without alteration. The vector molecule was also found to exist in relatively low copy number compared to other Dictyostelium vectors in the transformed cells. We demonstrated the utility of this vector as a reporter vector with glycogen synthase promoter/luc fusions of varying sizes.     

马尾松毛虫的光周期反应

马尾松毛虫Dendrolimus punctatus Walker和油松毛虫 Dendrolimus tabulaeformisTsai et Liu都属于长日照型昆虫。它们的光周期反应却存在着明显的差开。马尾松毛虫初龄幼虫对光照时数虽然敏感,可是只有在整个幼虫期都处在短光照周期条件下才能维持幼虫的滞育。 而且, 幼虫的滞育强度明显较弱,解除滞育所要求的条件也不如油松毛虫严格。在较高温度条件下,幼虫的滞育更不稳定,一般仅表现为生长的短暂停滞和幼虫历期的相对延长。温度和光周期还可影响到幼虫的存活和性比。马尾松毛虫幼虫呈典型的浅滞育现象。正是由于这一特性,在环境条件的影响下,长江沿岸省份不同年份马尾松毛虫二、三代分化的比例才有较大的波动,这直接关系着当地的种群动态,也是当年当地高虫口区二代虫能否成灾的关键。     

植被生态信息的典范相关分析技术理论

植被生态信息分析中对两（多）组取样集间的相关分析的需求导致了典范相关分析技术的应用和发展。本文对典范相关分析技术的原理、典范参数的生态学意义进行了提示,比较了典范相关分析与ＰＣＡ之间的差异,产在典范相关分析技术的应用过程中,原始数据的预处理提出了建议。     

Fertile plants regenerated from suspension culture-derived protoplasts of an indica type rice (Oryza sativa L.)

Calluses were induced from immature embryos of an indica type rice and finely dispersed cell suspension cultures were initiated from the callus using modified AA medium (S₁ medium). The suspension cultures were maintained alternatively (1–2 passages in each medium) in S₁ medium and S₂ medium, the latter containing KNO₃, NH₄NO₃, proline and glutamine as nitrogen source. Protoplasts of high quality were isolated form suspension cells cultured in S₂ medium supplemented with ABA. Embedding the protoplasts in agarose blocks containing NH₄NO₃-free modified KM8P(PM₁) medium and immersing the blocks in NH₄NO₃-containing modified KM8P(PM₃) medium were most effective for obtaining protoplast division and callus formation. The protoplast-derived calluses were precultured in potato extract-aand/or ABA-containing N₆(D₁, D₂ or D₃) media and many embryo-like structures were formed. These structures developed into plantlets after being transferred to N₆ differentiation (D₄) medium. The regenerated plantlets grew into mature plants and beard seeds normally.Abbreviations AA medium amino acids based medium - ABA abscisic acid - BA benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - DF division frequency - IAA indoleacetic acid - KIN kinetin - NAA naphthaleneacetic acid - PE planting efficiency     

Target determination of neurotransmitter phenotype in sympathetic neurons

While the majority of sympathetic neurons are noradrenergic, a minority population are cholinergic. At least one population of cholinergic sympathetic neurons arises during development by a target-dependent conversion from an initial noradrenergic phenotype. Evidence for retrograde specification has been obtained from transplantation studies in which sympathetic neurons that normally express a noradrenergic phenotype throughout life were induced to innervate sweat glands, a target normally innervated by cholinergic sympathetic neurons. This was accomplished by transplanting footpad skin containing sweat gland primordia from early postnatal donor rats to the hairy skin region of host rats. The sympathetic neurons innervating the novel target decreased their expression of noradrenergif traints and developed choline acetyltransferase (ChAT) activity. In addition, many sweat gland-associated fibers acquired acetylcholinesterase (AChE) staining and VIP immunoreactivity. These studies indicated that sympathetic neurons in vivo alter their neurotransmitter phenotype in response to novel envronmental signals and that sweat glands play a critical role in the cholinergic and peptidergic differentiation of the sympathetic neurons that innervate them. The sweat gland-derived cholinergic differentiation factor is distinct from leukemia inhibitory factor and ciliary neurotrophic factor, two well-characterized cytokines that alter the neurotransmitter properties of cultured sympathetic neurons in a similar fashion. Recent studies indicate that anterograde signalling is also important for the establishment of functional synapses in this system. We have found that the production of cholinergic differentiation activity by sweat glands required sympathetic innervation, and the acquisition and maintenance of secretory competence by sweat glands depends upon functional cholinergic innervation. 1994 John Wiley & Sons, Inc.     

急性低氧对大鼠脑组织钙调素含量及其依赖性蛋白激酶Ⅱ活性的影响

本实验观察了活性钙调素（ＣａＭ）含量和ＣａＭ依赖性蛋白激酶Ⅱ（ＣａＭｋｉｎａｓｅⅡ）活性在急性低氧（模拟海拔７０００ｍ,５ｈ）和常氧对照大鼠脑子组织中的变化。用流式产胞仪（ＦＡＣＳ）所测两组动物脑皮层细胞的ＣａＭ,平均荧光强度分别为４０．０±４．９和４６．１±５．８,急性低氧组明显低于常氧对照组（Ｐ＜０．０５）;用同位素液闪计数法所测两组动物皮层脑匀浆提取液中ＣａＭｋｉｎａｓｅⅡ活性,分别为１８４．３±８．１和１９８．８±９．４ｐｍｏｌＰｉ·ｍｉｎ－１·ｍｇ－１ｐｒｏ,急性低氧组明显低于常氧对照组（Ｐ＜０．０１）。结果提示ＣａＭ和ＣａＭｋｉｎａｓｅⅡ对低氧较为敏感,急性低氧时中枢神经细胞结构或功能的紊乱可能与活性ＣａＭ的含量减少和ＣａＭｋｉｎａｓｅⅡ活性能下降有关。     

方程dx/dt=f(x(t-1))具有多个周期的周期解并蕴含浑沌的条件

本文给出了方程dx/dt=f(x(t-1))出现4/(2n 1),4/(2n-1),4/(2n-3),…,4/7,4/5,4/3,4一周期解并蕴含浑沌的一个条件。     

醋酸钙复盐对微生物生长的影响

应用四醋酸钙对黑曲霉、黄曲霉、米曲霉、链格孢霉等霉菌和大肠杆菌、枯草杆菌、绿脓杆菌、金黄色葡萄球菌等细菌生长影响作了研究,并将四醋酸钙与醋酸钙、苯甲酸钠对上述微生物的生长抑制作用加以比较。0.4％四醋酸钙对上述细菌的生长有明显的抑制作用。对上述霉菌生长亦有一定的抑制作用。当其与苯甲酸钠协同使用时,能更明显地抑制微生物生长。实验结果表明四醋酸钙很可能是一种安全性高、成本低的新型食品防腐剂。     

新经济植物黑莓的引种

黑莓（Ｒｕｂｕｓｓｐｐ．）是第三代新兴的小果类果树之一。江苏省植物研究所于１９８６～１９８８年从美国引进了７个黑莓品种,从中选出适合江苏地区栽培的Ｈｕｌｌ,Ｃｈｅｓｔｅｒ,Ｂｌａｃｋｓａｔｉｎ３个品种,并已初步推广。田间试验对３个品种的发枝习性、开花结果习性和产量构成等进行比较。Ｈｕｌｌ单株产量最高,果实最大,ＢｌａｃｋＳａｔｉｎ单株产量最低,果实最小。但若种植密度适宜,３品种均能达到高产。     

几种沙漠地区野生药用植物资源及其引种栽培

几种沙漠地区野生药用植物资源及其引种栽培尹林克（中国科学院吐鲁番沙漠植物园,新疆吐鲁番８３８００８）Ｒｅｓｏｕｒｃｅｓｏｆｓｅｖｅｒａｌｓｐｅｃｉｅｓｏｆｗｉｌｄｍｅｄｉｃｉｎａｌｐｌａｎｔｓｉｎｄｅｓｅｒｔｒｅｇｉｏｎａｎｄｔｈｅｉｒｉｎｔｒｏｄｕ...