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31.
32.
Seven novel cell lines from canine histiocytic sarcoma (HS), three of which were disseminated cutaneous HS and four of which were synovial HS, were established. All of the established cell lines had the same morphological (by light and electron microscopic findings), cytochemical (alpha-naphthyl butyrate esterase-positive), and immunohistochemical (vimentin- and lysozyme-positive, and cyto-keratin-negative) characteristics as the original HS tumor cells. All of the established cell lines injected into nude mice subcutaneously produced solid tumors. Because the established cell lines also showed phagocytic and processing activities, the HS tumor cells appear to originate from the mononuclear phagocytic system cells, despite their differences in locations or organs.  相似文献   
33.
We have identified various lactoferrin (Lf) molecules in mastitic mammary gland secretions (MGSs), and these Lf molecules were examined for their physiological function in MG. These Lf molecules were isolated by Con A affinity chromatography, and then analyzed by various electrophoresis methods and N-terminal amino acid sequencing. The low Con A affinity Lf was found to have low molecular peptides as compared with the 86 kDa of the high Con A affinity Lf, which is usually detected in healthy MGSs. The N-terminal amino acid sequence of each of the small molecular Lfs were confirmed as fragments of 86 kDa Lf. This low Con A affinity Lf stimulated spleen adherent cells to produce more O(2)(-) than 86 kDa Lf. Furthermore, the low Con A affinity Lf showed low antibacterial activity against E. coli and S. aureus, and had decreased iron-binding capacity in comparison with 86 kDa Lf. Moreover, the 86 kDa Lf could stimulate bovine T cells or macrophages to produce IFN-gamma, IL-4, IL-6, and IL-1alpha. However low Con A affinity Lf induced the production of TNFalpha, but not physiological T cell or macrophage cytokines. It was also found that when the healthy MGs of dry cows were injected with the low Con A affinity Lf, there was an increase in polymorphonuclear cells together with TNFalpha, MCP-1, and IL-8 production. These results suggested that low Con A affinity Lf in mastitic MGSs differed from 86 kDa Lf in physiological characteristics, and, that it induced an inflammatory reaction in MGs.  相似文献   
34.
In a previous study, we developed male sterile lines of Japanese bunching onion (Allium fistulosum L.) possessing the cytoplasm of a wild species, A. galanthum Kar. et Kir., by backcrossing. To evaluate seed productivity of the male sterile lines in practise, they were crossed with the male fertile line, cultivar 'Kujyo', using honeybees as pollinators under field conditions. The number of florets and seeds per inflorescence, seed set and seed germination of the material were investigated. Although variation was observed among the male sterile lines, there were several lines having seed productivity equal to cultivar 'Kujyo'. Our data demonstrate that the male sterile lines of A. fistulosum possessing the cytoplasm of A. galanthum are useful as seed parents for the commercial F seed production of A. fistulosum.  相似文献   
35.
The impact cratering process on a comet is controversial but holds the key for interpreting observations of the Deep Impact collision with comet 9P/Tempel 1. Mid-infrared data from the Cooled Mid-Infrared Camera and Spectrometer (COMICS) of the Subaru Telescope indicate that the large-scale dust plume ejected by the impact contained a large mass (approximately 10(6) kilograms) of dust and formed two wings approximately +/-45 degrees from the symmetric center, both consistent with gravity as the primary control on the impact and its immediate aftermath. The dust distribution in the inner part of the plume, however, is inconsistent with a pure gravity control and implies that evaporation and expansion of volatiles accelerated dust.  相似文献   
36.
Stem cell self-renewal can be specified by local signals from the surrounding microenvironment, or niche. However, the relation between the niche and the mechanisms that ensure the correct balance between stem cell self-renewal and differentiation is poorly understood. Here, we show that dividing Drosophila male germline stem cells use intracellular mechanisms involving centrosome function and cortically localized Adenomatous Polyposis Coli tumor suppressor protein to orient mitotic spindles perpendicular to the niche, ensuring a reliably asymmetric outcome in which one daughter cell remains in the niche and self-renews stem cell identity, whereas the other, displaced away, initiates differentiation.  相似文献   
37.
Molecular dependence of vesicular endocytosis was investigated with capacitance measurements at the calyx of Held terminal in brainstem slices. Intraterminal loading of botulinum toxin E revealed that the rapid capacitance transient implicated as "kiss-and-run" was unrelated to transmitter release. The release-related capacitance change decayed with an endocytotic time constant of 10 to 25 seconds, depending on the magnitude of exocytosis. Presynaptic loading of the nonhydrolyzable guanosine 5'-triphosphate (GTP) analog GTPgS or dynamin-1 proline-rich domain peptide abolished endocytosis. These compounds had no immediate effect on exocytosis, but caused a use-dependent rundown of exocytosis. Thus, the guanosine triphosphatase dynamin-1 is indispensable for vesicle endocytosis at this fast central nervous system (CNS) synapse.  相似文献   
38.
We found that, in the mouse visual cortex, action potentials generated in a single layer-2/3 pyramidal (excitatory) neuron can reliably evoke large, constant-latency inhibitory postsynaptic currents in other nearby pyramidal cells. This effect is mediated by axo-axonic ionotropic glutamate receptor-mediated excitation of the nerve terminals of inhibitory interneurons, which connect to the target pyramidal cells. Therefore, individual cortical excitatory neurons can generate inhibition independently from the somatic firing of inhibitory interneurons.  相似文献   
39.
Using a high-sensitivity torsional oscillator (TO) technique, we mapped the rotational and relaxational dynamics of solid helium-4 ((4)He) throughout the parameter range of the proposed supersolidity. We found evidence that the same microscopic excitations controlling the torsional oscillator motions are generated independently by thermal and mechanical stimulation. Moreover, a measure for the relaxation times of these excitations diverges smoothly without any indication for a critical temperature or critical velocity of a supersolid transition. Finally, we demonstrated that the combined temperature-velocity dependence of the TO response is indistinguishable from the combined temperature-strain dependence of the solid's shear modulus. This implies that the rotational responses of solid (4)He attributed to supersolidity are associated with generation of the same microscopic excitations as those produced by direct shear strain.  相似文献   
40.
The seeds of Monochoria vaginalis require light to germinate. However, they are able to germinate in darkness in the presence of rice hulls. The mechanism of this phenomenon was investigated in this study, in which only the unsterilized seeds of Monochoria were induced to germinate by the presence of a rice hull extract. The rice hull extract was able to be replaced by either a mixture of amino acids and phosphate or a yeast extract. The culture media in which germination was observed always showed turbidity, indicating the propagation of bacteria, which were identified as Bacillus sp., Pedobacter sp., Pantoea sp. and Sphingomonas sp. Treatment with the individual bacterial species or combinations of these bacteria induced Monochoria seed germination when added to the media containing the rice hull extract. It was concluded that the rice hull extract accelerates the propagation of bacteria, which in turn digest the seed coat of Monochoria, facilitating its germination.  相似文献   
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