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排序方式: 共有336条查询结果,搜索用时 6 毫秒
51.
Claudio De Nardi Simone Braggio Luca Ferrari Stefano Fontana 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,762(2)
A rapid, selective and accurate high-performance liquid chromatography–tandem mass spectrometry assay for the quantification of sanfetrinem in human plasma has been developed and validated. The performance of manual and automated sample preparation was assessed; 50 μl of plasma sample was deproteinized with acetonitrile, followed by dilution with water and injection onto the LC system. Chromatographic separation was achieved on a Phenomenex Luna C18(2), 50×2.0 (5 μm) column with a mobile phase consisting of water–acetonitrile with 0.1% formic acid followed by detection with a Perkin-Elmer API3000 mass spectrometer in multiple reaction monitoring mode. The lower limit of quantification was improved by five times compared to the UV method previously reported. A range of concentration from 10 ng/ml to 5 μg/ml was covered. The method was applied to the quantification of sanfetrinem in human plasma samples from healthy volunteers participating in a clinical study. 相似文献
52.
Casein Utilization by Streptococcus thermophilus Results in a Diauxic Growth in Milk 总被引:1,自引:0,他引:1 下载免费PDF全文
Catherine Letort Michle Nardi Peggy Garault Vronique Monnet Vincent Juillard 《Applied microbiology》2002,68(6):3162-3165
In milk, Streptococcus thermophilus displays two distinct exponential growth phases, separated by a nonexponential one, during which proteinase synthesis was initiated. During the second exponential phase, utilization of caseins as the source of amino acids resulted in a decrease in growth rate, presumably caused by a limiting peptide transport activity. 相似文献
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54.
V. Grosso A. Farina D. Giorgi L. Nardi G. Diretto S. Lucretti 《Plant Cell, Tissue and Organ Culture》2018,132(1):57-70
Orchids of the genus Dendrobium hold a high economical value in the international markets both as pot plants or cut flowers, and for the production of some metabolites with antioxidant and anti-tumoral activities. Manipulating ploidy levels of Dendrobium species is one of the possible methods to develop new varieties with increased ornamental value and a higher production of secondary metabolites. In this work, we present a new and fast flow cytometry approach to obtain and select Dendrobium phalaenopsis?×?Dendrobium loddigesii polyploids, through an early in vitro screening on protocorm like bodies (PLBs) after antimitotic treatment. Our approach allows the identification of the best time of treatment on control PLBs and the assessment of best conditions for polyploid recovery just one month after treatments, by using Cycle Value. We were able to discard about the two-third of the unchanged material by drastically reducing the explants to work with and the corresponding costs. Different conditions, regarding concentrations and exposition time, were tested using colchicine or amiprophos-methyl (APM). A high polyploids recovery, up to 80%, were obtained with both antimitotic agents, and those materials were further characterized by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS), to identify independent polyploids explants with increased levels in high-value molecules as shihunidine and hircinol, together with stochastic events and genotype-specific metabolite fluctuations. 相似文献
55.
Monoamine-Induced Apoptotic Neuronal Cell Death 总被引:5,自引:0,他引:5
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Ester Fonsatti Elda Lamaj Sandra Coral Luca Sigalotti Gianpaolo Nardi Aldo Gasparollo Mario P. Colombo Maresa Altomonte Michele Maio 《Cancer immunology, immunotherapy : CII》1999,48(2-3):132-138
Melanoma cells constitutively release intercellular adhesion molecule 1 (ICAM-1) as soluble ICAM-1 (sICAM-1), and its levels
are elevated in melanoma patients and correlate with disease progression. However, this correlation is not absolute, suggesting
that specific characteristics of neoplastic cells and/or ICAM-1-positive non-neoplastic cells may influence the amounts of
circulating sICAM-1. In this study, we found a weak correlation (r = 0.55; r
2 = 0.3) between sICAM-1 release by 40 metastatic melanomas (36 primary cultures and 4 cell lines), and ICAM-1 expression on
neoplastic cells. In addition, melanoma-secreted interleukin-1α (IL-1α) (1/40) but not vascular endothelial growth factor
(VEGF) (29/40), significantly (P < 0.05) up-regulated the shedding of sICAM-1 by human umbilical vein endothelial cells (HUVEC). This was completely abolished
by IL-1α/β neutralizing antibodies both at the protein and mRNA level. Altogether, our results suggest that (i) the extent
of sICAM-1 release is distinctive for individual melanomas and can be independent of ICAM-1 expression; (ii) tumor endothelia
may sustain levels of sICAM-1 in selected melanomas; (iii) melanoma-released VEGF does not affect ICAM-1 expression and sICAM-1
release by HUVEC. Melanoma-derived sICAM-1 inhibits cell-mediated cytotoxicity of melanoma cells; therefore, constitutive
levels of sICAM-1 release and IL-1α secretion by individual melanomas can differentially influence tumor progression and the
clinical effectiveness of cytotoxic-cell-based vaccines.
Received: 15 October 1998 / Accepted: 17 February 1999 相似文献
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59.
Giovanni Battista Conselvan Diego Pizzeghello Ornella Francioso Michele Di Foggia Serenella Nardi Paolo Carletti 《Plant and Soil》2017,420(1-2):119-134
Background and aims
Biostimulants are natural compounds that enhance plant growth and plant nutrient use efficiency. In this study, biostimulant effects of humic substances (HS) extracted from leonardites were analysed on the metabolism of maize plants grown in hydroponic conditions.Methods
HS extracted from four leonardites were tested for their auxin-like and gibberellin-like activities. Then, 11 day old maize seedlings were treated for 48 h with five concentrations (0, 0.1, 0.5, 1, and 10 mg C L?1) of HS. After sampling, root growth and morphology, glutamine synthetase (GS) activity, glutamate synthase (GOGAT) activity, total protein content, soluble sugars content, phenylalanine ammonia-lyase (PAL) activity, soluble phenols, and free phenolic acids were analysed.Results
HS from leonardites had similar spectroscopic pattern, with small differences. The HS from the South Dakota lignite (HS_USA) had more carboxylic groups, whereas the three from Turkish mines had more aromatic and aliphatic structures. HS_USA best enhanced total root growth, root surface area, and proliferation of secondary roots. Plant nutrient use efficiency was enhanced by HS_4, HS_USA and HS_B, with increment of GS and GOGAT enzymes activity and total protein production. HS stimulated also PAL enzyme activity, followed by a higher production of total soluble phenols, p-hydroxybenzoic acid, p-coumarilic acid, and chlorogenic acid.Conclusion
This study found that, although the activity of the HS depended on the origin of the leonardite, these compounds can be attributed to the biostimulant products, eliciting plant growth, nitrogen metabolism, and accumulation of phenolic substances.60.