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41.
Francesca Clementi Jone Rossi Lucia Costamagna Jolanda Rosi 《Antonie van Leeuwenhoek》1980,46(4):399-405
Schwanniomyces castellii and Endomycopsis fibuligera Produced extracellular amylase(s) when grown on various carbon sources and at different pH values. Both yeast species showed significant amylase synthesis in the presence of either maltose or soluble starch. On the other substrates tested (glucose, cellobiose, sucrose, trehalose, melezitose, raffinose, ethanol, glycerol) differences were found regarding growth and amylase production. Free glucose in the culture medium apparently inhibited enzyme synthesis. The pH range allowing maximal growth and amylase production was 4.5–6.0 for E. fibuligera and 5.5–7.0 for S. castellii. 相似文献
42.
3H-thymidine incorporation and DNA-polymerase activity during early hours of wheat embryo germination at two viability levels
have been studied. The patterns of two biosynthetic activities, as well as the dependence of DNA synthesis on protein synthesis,
indicated the presence of a delay in the early phase of imbibition of the aged embryos with respect to viable germs. 相似文献
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Vittoria Nuti Ronchi Lucia Giorgetti Mariagrazia Tonelli Guido Martini 《Plant Cell, Tissue and Organ Culture》1992,30(2):107-114
Cytological analysis of different carrot cell lines in culture has shown various cytogenetic anomalies generating new levels of ploidy and novel chromosome numbers. Polyploidy may be considered a reservoir of variability that can be released in the form of distinct new segregants of different ploidy. Mechanisms alternative to mitosis (reductional grouping, prophase chromosome reduction) operate from a polyploid state (possibly reached by means of endopolyploidy, endomitosis, nuclear fusion, or restitution nuclei) to generate new levels of ploidy and novel chromosome numbers necessary for selection to operate in vitro. The segregational phenomena require chromosome recognition in haploid set complements and abnormal behaviour of mitoses; the resulting chromosome variability suggests that chromosomes are arranged, in the resting nuclei, in an orderly and predictable manner.The knowledge of the molecular events governing these mechanisms, and how to control them, would be of great help for future applications of plant cell culture. 相似文献
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Scatter hoarding by kangaroo rats (Dipodomys merriami) and pilferage from their caches 总被引:9,自引:0,他引:9
Daly Martin; Jacobs Lucia F.; Wilson Margo I.; Behrends Philip R. 《Behavioral ecology》1992,3(2):102-111
We observed radio-implanted Merriam's kangaroo rats disposingof 10-g bonanzas of rolled oats in 48 trials in the field. Theprincipal determinant of the initial disposition of discoveredfood was apparently its distance from the day burrow: food foundwithin about 10m was mainly larder hoarded, whereas food encounteredfarther afield was usually dispersed immediately in shallowcaches. Cache sites were newly dug for the purpose and not reused;most caches were nearer the current day burrow than was thefood source, but a few were placed far from both the cacher'sday burrow and its habitual nocturnal range. An experiment withartificial caches indicated that security from discovery increaseswith spacing and with proximity to perennial shrubs. Nine kangaroorats cached dyed food, and fecal dye traces revealed extensivepilferage from five of them, by both conspecifics and otherrodent species. Limited evidence indicates that food encounterednearer home and initially larder hoarded was more secure frompilferage than food initially scattered, and yet kangaroo ratswere observed to scatter caches soon after initial larder hoarding.A kangaroo rat whose dyed stores escaped pilferage fed fromthem at intervals for at least 12 days. Even cachers who incurredpilferage made as much, or more, use of their caches as anythief, suggesting that scattering caches may be a defense againstcatastrophic losses. 相似文献
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Bonacchi A Taddei ML Petrai I Efsen E Defranco R Nosi D Torcia M Rosini P Formigli L Rombouts K Zecchi S Milani S Pinzani M Laffi G Marra F 《Histology and histopathology》2008,23(3):327-340
The liver represents a site of expression of neurotrophins and their receptors. We have characterized the expression and intracellular localization of the nerve growth factor (NGF) receptor, Trk-A, in liver cells in vivo and in vitro. In both normal and fibrotic liver tissue, Trk-A immunostaining was present in different cell types, including parenchymal cells and cells of the inflammatory infiltrate. In hepatocytes and activated stellate cells (HSC), Trk-A showed a predominant nuclear localization, both in the presence and absence of injury. In cultured HSC, Trk-A was found to be functional, because exposure of the cells to recombinant NGF resulted in stimulation of cell migration and activation of intracellular signaling pathways, including Ras-ERK and PI3K/Akt. Remarkably, in cultured HSC, Trk-A staining was found constitutively in the nucleus. In these cells, Trk-A could be stained only by antibodies directed against the intracellular domain but not by those recognizing the extracellular portion of Trk-A suggesting that the intracellular portion of the receptor is the major determinant of nuclear Trk-A staining. In contrast to HSC, freshly isolated hepatocytes did not show any nuclear localization of the intracellular portion of Trk-A. In pheocromocytoma cells, nuclear staining for Trk-A was not present in conditions of serum deprivation, but could be induced by exposure to NGF or to a mixture of soluble mediators. We conclude that nuclear localization of the intracellular domain of Trk-A is observed constitutively in liver cells such as HSC, while in other cell types it could be induced in response to soluble factors. 相似文献
50.
Toward an Overall Analytical Framework for the Integrated Sustainability Assessment of the Production and Supply of Raw Materials and Primary Energy Carriers
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Jo Dewulf Lucia Mancini Gian Andrea Blengini Serenella Sala Cynthia Latunussa David Pennington 《Journal of Industrial Ecology》2015,19(6):963-977
The sustainable production and supply of raw materials (“nonenergy raw materials”) and primary energy carriers (“energy raw materials”) is a core element of many policies. The natural resource base for their production and supply, and the access thereto, are limited. Moreover, raw material supply is high on environmental and social impact agendas as well. A broad, quantitative framework that supports decision makers is recommended so as to make use of raw materials and primary energy carriers more sustainably. First, this article proposes a holistic classification of raw materials and primary energy carriers. This is an essential prerequisite for developing an integrated sustainability assessment framework (ISAF). Indeed, frequently, only a subset of raw materials and primary energy carriers are considered in terms of their source, sector, or final application. Here, 85 raw materials and 30 primary energy carriers overall are identified and grouped into seven and five subgroups, respectively. Next, this article proposes a quantitative ISAF for the production and supply of raw materials and primary energy carriers, covering all the sustainability pillars. With the goal of comprehensiveness, the proposed ISAF integrates sustainability issues that have been covered and modeled in quite different quantitative frameworks: ecosystem services; classical life cycle assessment (LCA); social LCA; resource criticality assessment; and particular international concerns (e.g., conflict minerals assessment). The resulting four areas of concerns (i.e., environmental, technical, economic, and social/societal) are grouped into ten specific sustainability concerns. Finally, these concerns are quantified through 15 indicators, enabling the quantitative sustainability assessment of the production and supply of raw materials and primary energy carriers. 相似文献