梭曼等胆碱酯酶抑制剂对猫膈神经单纤维电活动的影响

在麻醉猫,经推动脉注入梭曼、VX,沙林及乙酰甲胆碱引起呼吸中枢严重抑制的剂量分别为0.5—1、3、15、2001μg/头;但在无麻醉、箭毒麻痹、人工呼吸并用药物保护循环的清醒猫,VX用量要增加十多倍,沙林用量增加2～8倍,棱曼用量不变。在严重抑制剂量的给药早期,梭曼使34.8％动物较早地出现膈神经单纤维放电加强,其每次吸气放电的冲动频率由20～30Hz增至50～80Hz,冲动个数由15～25个/每次放电增至40～60个/每次放电,兴奋持续短、迅速转入抑制且不易自动恢复;VX和乙酰甲胆碱使100％动物出现显著的放电加强,其冲动频率由20～30Hz增至70～130Hz、冲动个数由15～25个/每次放电增至60～80个/第次放电,兴奋持续时间较长、转入抑制慢但自动恢复较快;沙林使76.9％动物出现放电加强,其他表现类似VX。三种胆碱酯酶抑制剂和乙酰甲胆碱共使33/52根单纤维放电发生时相变化。结果表明:梭曼对呼吸中枢作用最强、沙林次之、VX最弱且更似乙酰甲胆碱。     

Mutagenicity of drinking water detected by the Tradescantia micronucleus test

Spring Lake reservoir of Macomb, Illinois, is a typical model of the drinking water supply of some midwestern towns of the United States. Water samples collected periodically in 1980 and 1981 from this lake were tested for mutagenicity using the Tradescantia micronucleus (Trad-MCN) test, a highly sensitive mutagen-detecting bioassay. Water samples from 1981 were also analyzed chemically. The micronucleus (MCN) frequency peaked (12-14 MCN/100 tetrads) in mid-July in both years, as compared with the average frequency (5 MCN/100 tetrads) of the base-line control that was maintained in nutrient solution (prepared with distilled water and pure chemicals). Drinking water from the tap was tested in parallel with lake water, and its mutagenicity tended to fluctuate with the mutagenicity of the lake water.     

Structural and functional analysis of the respiratory burst in the phagocytosing macrophage

The interrelation between structural changes and oxygen consumption by the phagocyting macrophage was studied. The mean number of phagocyted particles was estimated by the method of stereological transformation. It is found that the uptake of yeast particles and CN- -nonsensitive oxygen consumption is related to the concentration of yeast cells in the incubation medium. A positive correlation was established between the oxygen consumption and the mean number of phagocyted particles. The results obtained may suggest that the "respiration burst" takes place in the contact area of the macrophage and the phagocyted material, and its extent probably depends on the surface of that contact area.     

Characterization and evolution of a single-copy sequence from the human Y chromosome.

To study the evolution and organization of DNA from the human Y chromosome, we constructed a recombinant library of human Y DNA by using a somatic cell hybrid in which the only cytologically detectable human chromosome is the Y. One recombinant (4B2) contained a 3.3-kilobase EcoRI single-copy fragment which was localized to the proximal portion of the Y long arm. Sequences homologous to this human DNA are present in male gorilla, chimpanzee, and orangutan DNAs but not in female ape DNAs. Under stringent hybridization conditions, the homologous sequence is either a single-copy or a low-order repeat in humans and in the apes. With relaxed hybridization conditions, this human Y probe detected several homologous DNA fragments which are all derived from the Y in that they occur in male DNAs from humans and the apes but not in female DNAs. In contrast, this probe hybridized to highly repeated sequences in both male and female DNAs from old world monkeys. Thus, sequences homologous to this probe underwent a change in copy number and chromosomal distribution during primate evolution.     

白头翁的受精及组织化学研究

成熟花粉为二细胞,生殖细胞的蛋白质染色较营养细胞的深,淀粉粒充满营养细胞。花粉管常见穿人正在退化中的助细胞,并释放出两个精子,大量稠浓的蛋白质和淀粉,个别的释放在助细胞与胚囊壁之间。在一些卵细胞核,次生核(或极核)中,受精前后有1—3个小核仁(约1微米);助细胞具丝状器;反足细胞宿存,具多核和多核仁。胚囊中各个细胞的原生质稠浓程度和蛋白质染色深浅不同,其中以反足细胞和助细胞的原生质最稠浓,蛋白质染色最深。淀粉十分贫乏,绝大多数卵细胞,中央细胞和几乎全部助细胞和反足细胞均不含淀粉。双受精属于有丝分裂前类型,两性核融合步骤为:精子核接近和贴附在卵核和次生核上(或极核上),两性核的核膜溶解,其染色质沉入融合核,并随之松解,同时出现雄性核仁,最终,雄性核仁和雌性核仁合并,形成具单核和单核仁的合子和初生胚乳细胞。另外,雄性核仁同卵核仁合并较雄性核仁和次生核的晚,所以卵细胞完成受精较次生核晚。     

Stimulation of arachidonic acid metabolism: differences in potencies of recombinant human interleukin-1 alpha and interleukin-1 beta on two cell types

Recombinant human interleukin-l (rIL-1) alpha and beta, which have 26% homology in their amino acid sequence, stimulated arachidonic acid metabolism by squirrel monkey smooth muscle cells and rat liver cells; their relative effectiveness, however, varied with the two cells. Recombinant IL-1 alpha was 3 times more effective than rIL-1 beta at stimulating arachidonic acid metabolism by the primate smooth muscle cells. Recombinant IL-1 alpha was 3 times less effective than rIL-1 beta when measured by their capacity to synergistically stimulate arachidonic acid metabolism of rat liver cells in the presence of palytoxin and anti-diuretic hormone (ADH). The rIL-1 alpha and rIL-1 beta also stimulated the release of radiolabelled arachidonic acid from the smooth muscle cells prelabelled with [3H]arachidonic acid. The two recombinant IL-1s have different heat stabilities, again when measured by their capacity to stimulate arachidonic acid metabolism; IL-1 alpha was more heat stable than IL-1 beta.     

The effect of temperature on the acetylcholinesterase activity of muscle microsomes

Membrane vesicles which constitute the sarcotubular system were separated and the fraction enriched in T-tubules purified by a calcium loading procedure. The preparations of unfractioned microsomes and T-tubules have been analyzed for their relative content of enzyme markers and acetylcholinesterase. The amount of this enzyme in the T-tubule fraction was higher than in mixed microsomes but less than two-fold the value of vesicles derived from sarcoplasmic reticulum. Arrhenius plots of membrane-bound and soluble acetylcholinesterase from either mixed microsomes or fractions enriched in T-tubules show an anomalous behaviour as two break points were obtained. The first discontinuity was found at about 17 degrees C for membrane-bound, and 12-14 degrees C for soluble acetylcholinesterase. The second one being at about 25 degrees C for both particulate and detergent-solubilized enzyme. The changes in activity with temperature suggest that lipid-protein, detergent-protein and protein-protein interactions might be involved in the stabilization of the enzyme both in the natural membrane and in the soluble state.     

Removal of239Pu from mice with 3,4,3 LICAM(C) or N,N′, N″, N‴-tetra-(2,3-dihydroxybenzoyl)-spermine

Summary Male mice SAS/4 were injected i.v. with²³⁹Pu citr(IV) 0.27 µCikg^–1–9.99 kBqkg^–1. After 1 h 30 µmol kg^–1 of 3,4,3 LICAM(C), N, N, N, N-tetra-(2,3-dihydroxybenzoyl)-spermine or Na₃CaDTPA as a reference compound was given intraperitoneally. After 4 days the animals were sacrified and the Pu content in livers, kidneys, femurs and carcasses was determined by the liquid scintillation method. It was found that, as compared with the control, 3,4,3 LICAM(C) removed 83% of the Pu activity deposited in the liver, 71% of that in the femur and 79% of the Pu in the whole body. The Pu content in the kidneys exceeded the control value by about 50%. Na₃CaDTPA removed 96, 86, 40 and 72% of plutonium from the liver, kidneys, femurs and carcasses respectively.Tetra-DHB-spermine caused the excretion of 50, 57 and 39% of Pu from liver, bone and whole body respectively. The retention of Pu in the kidneys was increased to 400% of the control value.     

Phylogenetic relationships in theSideritis leucantha group (Lamiaceae)

Six closely related taxa of the sect.Eusideritis of the genusSideritis (S. leucantha, S. pusilla, S. flavovirens, S. granatensis, S. biflora andS. osteoxylla) are analysed to elucidate their phylogenetic relationships and position within the sect.Eusideritis. Meiotic behaviour, karyotype features, size and fertility of pollen grains, DNA amounts and seed protein profiles are reviewed. A polyploid origin of the group (from x = 7) and the further diversification through dysploidy and chromosome repatterning is postulated.S. osteoxylla is apparently of hybrid origin.