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11.
Edda De Rossi Giovanna Riccardi Anna Maria Sanangelantoni Orio Ciferri 《FEMS microbiology letters》1985,30(1-2):239-244
Abstract A Spirulina platensis gene library has been constructed using cosmid vector pMMB34. The cosmid bank was controlled for its random gene distribution by colony hybridization. Genes were identified using either homologous or heterologous probes of genes involved in photosynthesis (large and small subunit of d -ribulose 1,5-bisphosphate carboxylase, 32 kDa thylakoid protein, α, β subunits of C-phycocyanin) and protein synthesis (elongation factors EF-Tu, EF-G). 相似文献
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Evolution of collagen IV genes from a 54-base pair exon: A role for introns in gene evolution 总被引:1,自引:0,他引:1
Giovanna Butticè Paul Kaytes Jeanine D'Armiento Gabriel Vogeli Markku Kurkinen 《Journal of molecular evolution》1990,30(6):479-488
The exon structure of the collagen IV gene provides a striking example for collagen evolution and the role of introns in gene evolution. Collagen IV, a major component of basement membranes, differs from the fibrillar collagens in that it contains numerous interruptions in the triple helical Gly-X-Y repeat domain. We have characterized all 47 exons in the mouse alpha 2(IV) collagen gene and find two 36-, two 45-, and one 54-bp exons as well as one 99- and three 108-bp exons encoding the Gly-X-Y repeat sequence. All these exons sizes are also found in the fibrillar collagen genes. Strikingly, of the 24 interruption sequences present in the alpha 2-chain of mouse collagen IV, 11 are encoded at the exon/intron borders of the gene, part of one interruption sequence is encoded by an exon of its own, and the remaining interruptions are encoded within the body of exons. In such "fusion exons" the Gly-X-Y encoding domain is also derived from 36-, 45-, or 54-bp sequence elements. These data support the idea that collagen IV genes evolved from a primordial 54-bp coding unit. We furthermore interpret these data to suggest that the interruption sequences in collagen IV may have evolved from introns, presumably by inactivation of splice site signals, following which intronic sequences could have been recruited into exons. We speculated that this mechanism could provide a role for introns in gene evolution in general. 相似文献
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Giovanna P. Marziani Longo Marcella Bracale Gianfranca Rossi Claudio P. Longo 《Plant molecular biology》1990,14(4):569-573
Cotyledons were excised from imbibed watermelon seeds, grown for 4 days in darkness on water or 10 M benzyladenine (BA) and then tested for the presence of the light-harvesting chlorophyll a/b protein (LHCP) and its mRNA. LHCP was assayed immunologically by western blotting of SDS gels: the protein was present in plastids, but it was not recovered with the thylakoid fraction. Antibodies directed against LHCP precipitated a 32 kDa polypeptide from translation products of poly(A) RNA of cotyledons only if these had been grown on BA. Taken together the data suggest that in absence of light cytokinins are necessary for the maintenance of a detectable level of LHCP-mRNA as well as for synthesis of the protein. 相似文献
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Abstract: Somatostatin (SS) is a neuropeptide that is distributed in various regions of the CNS, where it may act as a neurotransmitter or neuromodulator. SS produces multiple effects in the CNS through interactions with membrane receptors. In particular, SS inhibits various secretory responses in different cell types. In the present study, we have investigated the effects of exogenous application of SS on the intracellular free Ca2+ concentration ([Ca2+ ]i ) in PC12 cells, a rat pheochromocytoma cell line. SS did reduce the magnitude of the secondary, maintained Ca2+ influx brought about by K+ depolarization. Similar effects were obtained with the application of SS analogues, such as d -Trp8 -SS, d -Trp8 - d -Cys14 -SS, CGP-23996, and SMS-201995. In addition, treatment with cyclo-SS, a SS antagonist, did not alter [Ca2+ ]i . Experiments with selective blockers of different voltage-dependent Ca2+ channels, such as methoxyverapamil (D600) and Ω-conotoxin GVIA, demonstrated that the effects of SS on [Ca2+ ]i were mediated by voltage-dependent Ca2+ channels of the L type. Control experiments with a membrane potential indicator, i.e., the fluorescent dye bisoxonol, excluded that SS influenced the level of the membrane potential. SS effects on PC12 cells suggest the possibility that this neuropeptide plays a role in the modulation of cell functional activity by altering Ca2+ influx. 相似文献
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Giovanna Zolese Ileana Giambanco Giovanna Curatola Roberto Staffolani Enrico Gratton Rosario Donato 《Cell calcium》1996,20(6):465-474
Phase-modulation fluorescence lifetime measurements were used to study the single Trp residue of the Ca2+-binding protein S-100a both in the absence and in the presence of Ca2+ and/or Mg2+. Trp fluorescence decay for the protein was satisfactorily described by Lorentzian lifetime distributions centered around two components (approximately 4 ns and 0.5 ns). Lifetime values were unchanged by 2 mM Ca2+, but the fractional intensity associated with longer lifetime increased up to 75%. In the presence of Mg2+, the Ca2+ induced increase of the fractional intensity associated with longer lifetime was only 57%. For the protein in buffer, about the 85% of the recovered anisotropy was associated to a rotational correlation time of 6.7 ns. After the addition of Ca2+, this value was increased to 16.08 ns. In the presence of Mg2+, Ca+2 increased the rotational correlation time to 33.75 ns. Similar studies were performed with S-100a interacting with egg phosphatidylcholine vesicles (SUV). Our data suggest that the conformation of the protein may be influenced by structural features of the lipidic membrane. Moreover, data obtained in the presence of Mg2+ indicate some interaction between lipids and S-100, likely mediated by this ion. 相似文献
20.
Drought signal transduction in plants 总被引:5,自引:0,他引:5
Anders B. Jensen Peter K. Busk Mercé Figueras M. Mar Albà Giovanna Peracchia Ramon Messeguer Adela Goday Montserrat Pagès 《Plant Growth Regulation》1996,20(2):105-110
Water deficit is one of the most common environmental limitations of crop productivity by affecting growth through alterations in metabolism and gene expression. The mechanisms involved in drought perception and signal transduction pathways are poorly understood. The participation of the plant hormone abscisic acid (ABA) has been well established. ABA levels increase when there are changes in the environment that result in cellular dehydration. Different approaches have been taken to understanding the molecular responses to desiccation and how ABA regulates gene expression. Recent efforts have identified particular topics of importance in the dissection of the signal transduction pathway which are summarized as follows: physiological approaches: identification of signalling molecules. Genetic approaches: the use of mutants, and Molecular approaches: promoter analysis. 相似文献