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71.
Methanospirillum hungatei gave a positive chemotactic response to acetate. 相似文献
72.
Fiorenzo A. Peverali Maurizio D'Esposito Dario Acampora Giuseppe Bunone Mario Negri Antonio Faiella Anna Stornaiuolo Maria Pannese Enrica Migliaccio Antonio Simeone Giuliano Della Valle Edoardo Boncinelli 《Differentiation; research in biological diversity》1990,45(1):61-69
Mammalian genes containing a class-I homeobox (HOX genes) are highly expressed in the embryonic nervous system. As a first step towards the molecular analysis of the role these genes play in neural cells, we studied the expression of four human HOX genes in five neuroblastoma (NB) cell lines - SK-N-BE, CHP-134, IMR-32, SK-N-SH and LAN-1 - during the process of differentiation induced by treatment with retinoic acid (RA). The four genes, HOX1D, 2F, 3E and 4B, located at corresponding positions in the four HOX loci, share a high degree of sequence similarity with the Drosophila Deformed homeotic gene and constitute a homology group, group 10. One of these genes, HOX1D, is not expressed in the cells used, whereas the other three are highly expressed in untreated and RA-induced NB cells, even though the expression pattern in the various lines is slightly different for the three genes. Our analysis reveals a complex and specific expression pattern in these lines, paving the way to an identification of different NB-cell populations by means of specific HOX gene expression schemes. On the other hand, in every line studied, morphological maturation toward a neuronal differentiated phenotype appears to be associated with increased HOX gene expression. 相似文献
73.
Anna L. Ballard Alastair G. McEwan David J. Richardson J. Baz Jackson Stuart J. Ferguson 《Archives of microbiology》1990,154(3):301-303
Rhodobacter capsulatus strain BK5 possesses a membrane bound respiratory nitrate reductase rather than the periplasmic enzyme found in other strains. The enzyme in strain BK5 is shown to be both functionally and structurally related to the nitrate reductase of Paracoccus denitrificans and Escherichia coli.Abbreviation TMAO
trimethylamine-N-oxide 相似文献
74.
Organization and nucleotide sequence of the genes for ribosomal protein S2 and elongation factor Ts in Spirulina Platensis 总被引:2,自引:0,他引:2
Anna Maria Sanangelantoni Raffaele C. Calogero Francesca R. Butarelli Caludio O. Gualerzi Orsola Tiboni 《FEMS microbiology letters》1990,66(1-3):141-146
A 6.5 kb region from the genome of the cyanobacterium Spirulina platensis was cloned using as a probe the Escherichia coli gene for ribosomal protein S2. Sequence analysis revealed, in this region, the presence of the gene for ribosomal protein S2 and part of the gene for the elongation factor Ts (EF-Ts). The arrangement rpsB-spacer-tsf resembles that reported for E. coli. The deduced amino acid sequences of the platensis S2 and EF-Ts show significant homology with the E. coli counterparts. 相似文献
75.
Karen J. Thompson 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,166(5):675-684
Summary Extracellular stimulation over the dorsal funiculus in the spinal cord of lampreys was found to selectively activate prolonged episodes of fictive arousal respiration (Figs. 1, 3). The induced episodes showed comparable increases in cycle frequency and motoneuron burst duration to the spontaneous arousal pattern observed in isolated brain preparations (Fig. 2). Intracellular stimulation of primary sensory neurons with axons in the dorsal funiculus, called dorsal cells, also elicited the arousal pattern (Fig. 4). Mechanoreceptive dorsal cells respond to cutaneous stimulation. When mechanical stimuli were applied to the skin of intact lampreys (Fig. 6) or to lampreys with ipsilateral vagotomy, arousal respiration was induced (Figs. 7, 8). Bilateral, but not unilateral, trigeminal lesion blocked dorsal cell induction of the arousal response (Fig. 5). Spontaneous arousal respiration was recorded from intact, unrestrained lampreys (Fig. 9). These results suggest that fictive arousal respiration is the in vitro correlate of natural arousal respiration in lampreys, and that one mechanism leading to arousal respiration may be the activity of sensory dorsal cells. A model for respiratory motor pattern switching in lamprey is proposed. The model suggests that the normal and arousal patterns are produced by separately engaging rostral or caudal pattern generators in the medulla, rather than by modifying one pattern generator (Fig. 10). 相似文献
76.
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78.
Dawson K 《Bioethics》1988,2(1):1-14
A basic consideration in research on human embryos is the controversy about when the embryo acquires moral status. The author refutes the contention that segmentation is the determinant of moral status. She notes that segmentation, as a stage in embryonic development, does not coincide with the development of "irreversible individuality" upon which the segmentation argument depends. Dawson also finds a lack of clarity in the meaning of "individuality." These problems, she maintains, prevent segmentation from being morally important and render the proposed 14-day limit on embryo research unnecessary. Dawson concludes that to introduce a time restriction on embryo research is premature because it is based on an inadequate philosophical argument. 相似文献
79.
Hypothesis: A nicotine-dopamine interaction linking smoking with Parkinson's disease and tardive dyskinesia 总被引:2,自引:0,他引:2
Darrell G. Kirch Anna -Maria Alho Richard Jed Wyatt 《Cellular and molecular neurobiology》1988,8(3):285-291
1. Nicotine, an important pharmacological component of cigarette smoke, is known to have significant effects on central nervous system (CNS) dopaminergic function. Although acute doses of nicotine have been shown to facilitate dopamine release, recent data indicate that chronic nicotine treatment may actually decrease CNS dopamine turnover in the striatum. 2. A number of epidemiological investigations have demonstrated that individuals who are or who have been smokers are less likely to develop idiopathic Parkinson's disease (a disorder involving a deficit in nigrostriatal dopaminergic neurotransmission). In addition, there is preliminary evidence that individuals with tardive dyskinesia (a hyperkinetic movement disorder observed in some cases of chronic neuroleptic treatment and thought by some to be associated with striatal dopamine receptor supersensitivity) are more likely to be smokers. 3. A unitary hypothesis is presented, proposing that smoking in early adult life may decrease CNS catecholamine turnover, thereby protecting against free radical formation from catecholamine oxidation that in turn damages striatal neurons. These individuals are thereby "protected" from the later development of Parkinson's disease. In this hypothetical scheme, individuals who are given neuroleptics and who also are smokers may develop a greater degree of dopamine receptor supersensitivity due to combined receptor blockade by neuroleptics and a decrease in CNS dopamine turnover caused by nicotine, resulting in an increased prevalence of tardive dyskinesia in this group. 相似文献
80.
Karen Barsuhn S. Theodore Chester Jr. Dr. Jane A. Z. Leedle 《Current microbiology》1988,16(6):337-341
The effectiveness of a buffered sodium oleate solution was evaluated for detaching bacteria from ruminal digesta samples. A response surface derived from an octagonal design was used to determine the pH and concentration combination for maximum detachment of total and cellulolytic bacteria. The total number of bacteria detached increased up to 81% over control with treatment of a pH 8.8 and 1.5% sodium oleate solution. The recovery of cellulolytic bacteria was decreased to 35% of control with treatment of a pH 9.0 and 0.1% sodium oleate solution. Attempts to improve the recovery of viable bacteria exposed to sodium oleate solutions were unsuccessful. This response surface design identified an optimal pH and concentration that were consistent with existing information regarding detachment of total bacteria, and suggested that sodium oleate, at the concentrations tested, was toxic to the cellulolytic population of the rumen. 相似文献