Cytogenetic identification of interspecies cell-line contamination: procedures for non-cytogeneticists

A few simple procedures and cytological characteristics are described for identification of cell-line contamination involving human cells, or cells of several species of common laboratory and domestic animals. These include gross chromosome morphology, C-banding, fluorescence, and the nucleolus organizer regions as revealed by silver straining.     

The effect of sodium selenite toxicity on tissue distribution of zinc,iron, and copper in rats

Male Sprague-Dawley rats were used to determine the effects of suptoxic and toxic concentrations of selenite in the drinking water on tissue distribution of zinc (Zn), iron (Fe), and copper (Cu). Se (as sodium selenite) was provided in drinking water at concentrations of 0, 2, 4, and 8 ppm. At 19 d, half of the rats in 4 and 8 ppm Sesupplemented groups were kept on drinking water alone for additional 13 d. All rats were sacrificed at the end of 32 d of experiment. Heart, liver, and kidney were analyzed for the concentrations of Fe, Zn, and Cu by atomic absorption spectrophotometry and of Se by a fluorometric method. Results indicated that rats receiving 4 and 8 ppm Se in drinking water showed a marked reduction in food intake and a reduced growth rate. These adverse effects were quickly reversed when high Se intake was discontinued. Se toxicity caused minimal change in zinc status, reduced tissue iron concentrations and caused a marked increase in copper contents in heart, liver, and kidney. The latter findings were only partly reversed after removal of Se in drinking water. The accumulation of Cu in the tissues of Se-toxic rats provides the evidence of some interaction between Se and Cu.     

植物分类学中的繁殖生物学问题

繁殖生物学的知识有助于对分类学上复杂性问题的理解,从而大大地有利于我们作出明智的分类估价,但它不一定为我们提供解决问题的钥匙。异体受精增加群体的杂合性和变异性。互交繁育的程度限定了表型变异的式样;互交繁育受阻往往造成分类群表型上的间断。异形不亲和性系统(如花柱异长、雌雄异株等等)给分类学家提供可鉴别的形态差异来划分密切近缘的分类群,但也有由此而造成分类实践上混乱的情况。自体受精增加群体的纯合性;相继世代持续的自体受精使群体变成纯系或同形小种。但对自体受精植物的分类处理并不存在既定的原则,而现在大多数学者不支持把每一个纯系或小种(或约当种)都定为种的做法仅仅反映了当前分类学的时流。但普遍认为,对自体受精类群的分类处理应不同于异体受精类群。无融合生殖是自体受精的一种极端的形式,包括营养生殖和无融合结籽(包括不定胚生殖、无孢子生殖、双倍孢子生殖、假受精)两大类。在任何情况下,胚总是完全由母体组织形成,因此后代在遗传上与它的母体完全相同。由于许多无融合类群都是兼性的,即既能产生无性的种子,又能产生受精的种子,而且又常与杂交和多倍化密切相关,因此具有特别复杂的变异式样。这三套过程同时存在的类群,称为无融合种综,分类学上称为“困难属”,种的划     

小果青钱柳的分类地位

<正> 钟补求教授于1936年根据采自安徽黄山的模式标本而发表小果青钱柳Pterocarya mi-cropaliurus Tsoong新种时指出,该种与青钱柳的主要区别在于:(1)果实(包括果翅)较小,直径不超过2.5匣米,而在青钱柳则为3—7匣米;(2)果序较短,长约为青钱柳之半;(3)小叶数目较多,通常9—11枚,且较青钱柳为狭小;(4)小叶的锯齿较密较尖,最大的小叶通常每边有60个以上的锯齿,而在青钱柳则通常不到40个。但根据《中国植物志》第二十一卷(以下简称《植物志》),小果青钱柳应为青钱柳Cyclocarya paliurus(Batal.)Iljinsk.的异名。该《植物志》写道:“本种的小叶大小及数目、果翅的形状及大小变异极大,某些极端类型看来好象可以划分成各别的种,但都存在有中间类型,并且也无一定的地理分布限定,因此它必然是一个自然的种”。为此,我们对有关的腊叶材料进行了     

The lipid composition and conversion of tryptamine toN b-acetyltryptamine in aCatharanthus roseus cell line without indole alkaloids

Summary A cell line, NA13-2, was selected as a rapidly growing colony of protoplasts from a UV(254 nm)-fluorescent cell line, NA13-1, which originated from a tryptamine-resistant strain ofCatharanthus roseus NA13. Cell line NA13-2 lost the capability to produce indole alkaloids. Tryptophan fed to these cells was converted toN _b-acetyltryptamine as the major product. The free acetyl coenzyme A content of NA13-2 cells was 50% higher than in the mother cells. The total lipid content of the NA13-2 cells was 2.5-fold that in the NA13 cells. In spite of the similarity in the fatty acid content to that of the mother cell line NA13, the total lipid extract of NA13-2 cells appeared as a wax instead of an oil, resulting from the presence of sterol esters.This paper was presented in part at the Annual Meeting of the Society for Industrial Microbiology, Boston, MA, 1985, and the International Congress of the Plant Tissue Culture Association, Minneapolis, MN, 1986.     

The Onychophora of Trinidad, Tobago and the Lesser Antilles

This paper brings together the scattered literature on the Onychophora from Trinidad, Tobago and the Lesser Antilles. The 11 known species from this area are described, incorporating new material collected by the author. Scanning electron micrographs of the dorsal integument are presented for all but one species. Parthenogenesis is reported in a population of Epiperipatus imthurni from Trinidad.     

HIV-1 protease inhibitory activity of L-694,746, a novel metabolite of L-689,502.

L-689,502 is a potent inhibitor of HIV-1 protease activity in vitro. Microbial biotransformations of L-689,502 by cultures belonging to the genus Streptomyces sp. were performed. Extracts of culture broths were examined for the production of metabolites of L-689,502 that could inhibit HIV-1 protease activity. One culture, MA 6804 (Streptomyces lavendulae, ATCC 55095), produced L-694,746 that, while being structurally related to L-689,502, is a novel metabolite and a potent inhibitor of HIV-1 protease.     

Estradiol Secretion by Tadpole Ovaries Masculinized by Implanted Capsules of Cyanoketone

Female tadpoles of Rana catesbeiana were laparotomized at metamorphic stages XI-XIII and an empty capsule or one containing cyanoketone (CK), which is an inhibitor of Δ⁵-3β-hydroxysteroid dehydrogenase (Δ⁵-3β-HSD), was implanted intraperitoneally. Ovarian activity of Δ⁵-3β-HSD was examined histochemically 2 months later, estradiol-17β (E₂) secretion by the ovaries was measured by RIA 4 months later and histological changes of the ovaries were examined 6 months later. The Δ⁵-3β-HSD activity of the CK-treated ovaries was much lower than that of controls. E₂ secretion per froglet by CK-treated ovaries was about one third that of controls (p<0.001). Histological examination showed various degrees of masculinization of the ovaries, about 28% of which were totally transformed into testis-like structures.
As a result of suppressed Δ⁵-3β-HSD activity, dehydroepiandrosterone would have accumulated, resulting in deficient E₂ secretion and, therefore, ovarian masculinization. In tadpoles, this effect does not depend on the pituitary, whereas interrenal hyperplasia and hyperactivity do, indicating that interrenal function is not essential for ovarian masculinization. From these findings and our previous results, we suggest that disturbance of steroidogenesis by CK in the ovaries results in their masculinization.     

CME‐1, a novel polysaccharide,suppresses iNOS expression in lipopolysaccharide‐stimulated macrophages through ceramide‐initiated protein phosphatase 2A activation

CME‐1, a novel water‐soluble polysaccharide purified from Ophiocordyceps sinensis mycelia, has anti‐oxidative, antithrombotic and antitumour properties. In this study, other major attributes of CME‐1, namely anti‐inflammatory and immunomodulatory properties, were investigated. Treating lipopolysaccharide (LPS)‐stimulated RAW 264.7 cells with CME‐1 concentration‐dependently suppressed nitric oxide formation and inducible nitric oxide synthase (iNOS) expression. In the CME‐1‐treated RAW 264.7 cells, LPS‐induced IκBα degradation and the phosphorylation of p65, Akt and mitogen‐activated protein kinases (MAPKs), including extracellular signal‐regulated kinase, c‐Jun N‐terminal kinase and p38, were reduced. Treatment with a protein phosphatase 2A (PP2A)‐specific inhibitor, significantly reversed the CME‐1‐suppressed iNOS expression; IκBα degradation; and p65, Akt and MAPK phosphorylation. PP2A activity up‐regulation and PP2A demethylation reduction were also observed in the cells. Moreover, CME‐1‐induced PP2A activation and its subsequent suppression of LPS‐activated RAW 264.7 cells were diminished by the inhibition of ceramide signals. LPS‐induced reactive oxygen species (ROS) and hydroxyl radical formation were eliminated by treating RAW 264.7 cells with CME‐1. Furthermore, the role of ceramide signalling pathway and anti‐oxidative property were also demonstrated in CME‐1‐mediated inhibition of LPS‐activated primary peritoneal macrophages. In conclusion, CME‐1 suppressed iNOS expression by up‐regulating ceramide‐induced PP2A activation and reducing ROS production in LPS‐stimulated macrophages. CME‐1 is a potential therapeutic agent for treating inflammatory diseases.