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991.
Two acrasid cellular slime molds. Guttulinopsis vulgaris and G. nivea, are compared at the ultrastructural level. The amoebae of the two species are indistinguishable except for the presence of intranuclear fibers in G. vulgaris. Both species share some unusual features, including: plate-like cristae in the mitochondria, production of microbody-like organelles in the perinuclear space, spores with thin bilaminar walls, and stalks containing microfilaments bound in striated bundles. These and other observations are discussed with regard to the development of the sorocarps and the relationship of the genus to other members of the Acrasida. 相似文献
992.
993.
Indomethacin and substance BW-755C in experiments on isolated myometrium striae of pregnant white rats exert an inhibiting effect on the contractile uterus function due to inhibition of cyclooxygenase or lipoxygenase ways of the arachidonic acid transformation. Prostaglandin F2 alpha is sensitive to functioning of the cyclooxygenase and lipoxygenase ways of the arachidonic acid transformation, while oxytocin--only lipoxygenase one. Conclusions rest on results from multiparametric analysis of the contractile uterus function suggested by authors and confirmed by the pattern recognition method--the Karunen-Loev orthogonal decomposition. 相似文献
994.
J Shobha B Bhattacharyya D Balasubramanian 《Journal of biochemical and biophysical methods》1989,18(4):287-295
Enhancement of the fluorescence intensity of colchicine occurs in media of low polarity and appreciable viscosity; this is suggested to be the basis of the intensification of its fluorescence when it is bound to and immobilized in tubulin. We show here that the tubulin-bound fluorescence features of colchicine are largely reconstructed upon solubilizing it in chosen micellar aggregates that offer optimal polarities and microviscosities. Triton X-100 and bile salt micelles intensify the colchicine emission but the maximal effects are obtained with tetrameric aggregates of the peptide melittin. Estimates of the polarity, microviscosity and binding-site dimensions of colchicine are obtained using this mimetic approach. Our results suggest that well chosen micellar systems act as good models to reconstruct and analyze the spectral properties of molecules immobilized in their binding sites. 相似文献
995.
Isoproterenol-stimulated cyclic AMP (cAMP) accumulation in lymphocytes is an index of beta-adrenergic receptor functioning. It is not known if a delay between blood collection and subsequent cell preparation influences cAMP accumulation. We compared cAMP levels in lymphocytes processed from whole blood immediately after collection and following a 3.5 hour delay. There were no significant changes in either basal or stimulated levels of cAMP. This information may alleviate time constraints in certain experimental designs where immediate isolation of lymphocytes from whole blood may not be practical. 相似文献
996.
There was a range of severity of parasitism of stem-borer larvae by Hymenoptera and Nematoda and much premature death of the larvae. A nematode, Panagrolaimus rigidus, normally considered to be saprophytic, was implicated in some mortality of stem-borer larvae. 相似文献
997.
998.
999.
We here report the second record of a developmentally aberrant strain of a cellular slime mold from natural populations and demonstrate that this Dictyostelium mucoroides variant is capable of undergoing normal morphogenesis in the presence of the phycomycete fungus, Mucor hiemalis. The synergism is induced by an extracellular product(s) which is diffusable through thin agar membranes and is released by the fungus. The presence of the fungus not only induces stalk formation in this stalkless variant, but also increases the rate of sorocarp formation in 3 of 5 additional species of cellular slime molds assayed. 相似文献
1000.