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61.
Effects of over-expression of strictosidine synthase and tryptophan decarboxylase on alkaloid production by cell cultures of Catharanthus roseus 总被引:1,自引:0,他引:1
Camilo Canel M. Inês Lopes-Cardoso Serap Whitmer Leslie van der Fits Giancarlo Pasquali Robert van der Heijden J. Harry C. Hoge Robert Verpoorte 《Planta》1998,205(3):414-419
Cells of Catharanthus roseus (L.) G. Don were genetically engineered to over-express the enzymes strictosidine synthase (STR; EC 4.3.3.2) and tryptophan
decarboxylase (TDC; EC 4.1.1.28), which catalyze key steps in the biosynthesis of terpenoid indole alkaloids (TIAs). The cultures
established after Agrobacterium-mediated transformation showed wide phenotypic diversity, reflecting the complexity of the biosynthetic pathway. Cultures
transgenic for Str consistently showed tenfold higher STR activity than wild-type cultures, which favored biosynthetic activity through the
pathway. Two such lines accumulated over 200 mg · L−1 of the glucoalkaloid strictosidine and/or strictosidine-derived TIAs, including ajmalicine, catharanthine, serpentine, and
tabersonine, while maintaining wild-type levels of TDC activity. Alkaloid accumulation by highly productive transgenic lines
showed considerable instability and was strongly influenced by culture conditions, such as the hormonal composition of the
medium and the availability of precursors. High transgene-encoded TDC activity was not only unnecessary for increased productivity,
but also detrimental to the normal growth of the cultures. In contrast, high STR activity was tolerated by the cultures and
appeared to be necessary, albeit not sufficient, to sustain high rates of alkaloid biosynthesis. We conclude that constitutive
over-expression of Str is highly desirable for increased TIA production. However, given its complexity, limited intervention in the TIA pathway
will yield positive results only in the presence of a favorable epigenetic environment.
Received: 12 June 1997 / Accepted: 24 October 1997 相似文献
62.
Laura D'Alfonso Maddalena Collini Giancarlo Baldini 《European journal of biochemistry》2003,270(11):2497-2504
The stabilizing role of the disaccharide trehalose on beta-lactoglobulin (BLG) against its chemical denaturation both at native and acidic pH has been explored by means of time-resolved fluorescence of the probe acrylodan covalently bound to the unique free cysteine of BLG. The changes in acrylodan fluorescence lifetime with guanidinium chloride concentration reveal BLG sigmoidal denaturation profiles which depend upon the amount of trehalose in solution. When adding trehalose the transition midpoint shifts towards higher denaturant concentration. This effect has been measured by fitting the data with a two-state model whose parameters indicate that an almost 60% increase in the denaturation free energy is induced independently of trehalose concentrations and pH values. Fluorescence anisotropy measurements performed in the same conditions reveal that the internal dynamics are largely affected by the sugar, which makes the acrylodan environment more rigid, and by the denaturant that acts in the opposite way. The overall rotational diffusion of BLG suggests that trehalose affects the hydrodynamic properties of the solution in the proximity of the protein; tentative mechanisms are discussed. 相似文献
63.
Roberto Stella Giancarlo Biancotto Giorgio Arrigoni Federica Barrucci Roberto Angeletti Peter James 《Proteomics》2015,15(13):2332-2341
Despite the ban by the European Union, anabolic steroids might still be illicitly employed in bovine meat production. The surveillance of misuse of such potentially harmful molecules is necessary to guarantee consumers’ health. Analytical methods for drug residue control are based on LC‐MS/MS, but their efficacy can be hindered due to undetectable residual concentrations as a result of low‐dosage treatments. Screening methods based on the recognition of indirect biological effects of growth promoters’ administration, such as the alteration of protein expression, can improve the efficacy of surveillance. The present study was aimed at identifying modifications in the muscle protein expression pattern between bulls treated with an ear implant (Revalor‐XS®) containing trenbolone acetate (200 mg) and estradiol (40 mg), and untreated animals. The analysis of skeletal muscle was carried out using a tandem mass tags shotgun proteomics approach. We defined 28 candidate protein markers with a significantly altered expression induced by steroids administration. A subset of 18 candidate markers was validated by SRM and allowed to build a predictive model based on partial least square discriminant analysis. Our findings confirm the effectiveness of the proteomics approach as potential tool to overcome analytical limitations of drug residue monitoring. 相似文献
64.
Lamberto Manzoli Maria Elena Flacco Maria Fiore Carlo La Vecchia Carolina Marzuillo Maria Rosaria Gualano Giorgio Liguori Giancarlo Cicolini Lorenzo Capasso Claudio D'Amario Stefania Boccia Roberta Siliquini Walter Ricciardi Paolo Villari 《PloS one》2015,10(6)
Objective
To evaluate the safety and efficacy as a tool of smoking cessation of electronic cigarettes (e-cigarettes), directly comparing users of e-cigarettes only, smokers of tobacco cigarettes only, and smokers of both.Design
Prospective cohort study. Final results are expected in 2019, but given the urgency of data to support policies on electronic smoking, we report the results of the 12-month follow-up.Data Sources
Direct contact and structured questionnaires by phone or via internet.Methods
Adults (30–75 years) were included if they were smokers of ≥1 tobacco cigarette/day (tobacco smokers), users of any type of e-cigarettes, inhaling ≥50 puffs weekly (e-smokers), or smokers of both tobacco and e-cigarettes (dual smokers). Carbon monoxide levels were tested in a sample of those declaring tobacco smoking abstinence.Main Outcome Measures
Sustained smoking abstinence from tobacco smoking at 12 months, reduction in the number of tobacco cigarettes smoked daily.Data Synthesis
We used linear and logistic regression, with region as cluster unit.Results
Follow-up data were available for 236 e-smokers, 491 tobacco smokers, and 232 dual smokers (overall response rate 70.8%). All e-smokers were tobacco ex-smokers. At 12 months, 61.9% of the e-smokers were still abstinent from tobacco smoking; 20.6% of the tobacco smokers and 22.0% of the dual smokers achieved tobacco abstinence. Adjusting for potential confounders, tobacco smoking abstinence or cessation remained significantly more likely among e-smokers (adjusted OR 5.19; 95% CI: 3.35–8.02), whereas adding e-cigarettes to tobacco smoking did not enhance the likelihood of quitting tobacco and did not reduce tobacco cigarette consumption. E-smokers showed a minimal but significantly higher increase in self-rated health than other smokers. Non significant differences were found in self-reported serious adverse events (eleven overall).Conclusions
Adding e-cigarettes to tobacco smoking did not facilitate smoking cessation or reduction. If e-cigarette safety will be confirmed, however, the use of e-cigarettes alone may facilitate quitters remaining so.Registration Number
NCT01785537. 相似文献65.
Immunostaining for nucleophosmin in bone marrow trephine biopsy specimens in acute myeloid leukemias
66.
It is now clear that mitochondrial defects are associated with a large variety of clinical phenotypes. This is the result of the mitochondria's central role in energy production, reactive oxygen species homeostasis, and cell death. These processes are interdependent and may occur under various stressing conditions, among which low oxygen levels (hypoxia) are certainly prominent. Cells exposed to hypoxia respond acutely with endogenous metabolites and proteins promptly regulating metabolic pathways, but if low oxygen levels are prolonged, cells activate adapting mechanisms, the master switch being the hypoxia-inducible factor 1 (HIF-1). Activation of this factor is strictly bound to the mitochondrial function, which in turn is related with the oxygen level. Therefore in hypoxia, mitochondria act as [O2] sensors, convey signals to HIF-1directly or indirectly, and contribute to the cell redox potential, ion homeostasis, and energy production. Although over the last two decades cellular responses to low oxygen tension have been studied extensively, mechanisms underlying these functions are still indefinite. Here we review current knowledge of the mitochondrial role in hypoxia, focusing mainly on their role in cellular energy and reactive oxygen species homeostasis in relation with HIF-1 stabilization. In addition, we address the involvement of HIF-1 and the inhibitor protein of F1F0 ATPase in the hypoxia-induced mitochondrial autophagy. 相似文献
67.
Giorgio Lenaz Alessandra Baracca Giovanna Barbero Christian Bergamini Maria Elena Dalmonte Marianna Del Sole Marco Faccioli Anna Falasca Romana Fato Maria Luisa Genova Gianluca Sgarbi Giancarlo Solaini 《BBA》2010,1797(6-7):633-640
Recent investigations by native gel electrophoresis showed the existence of supramolecular associations of the respiratory complexes, confirmed by electron microscopy analysis and single particle image processing. Flux control analysis demonstrated that Complex I and Complex III in mammalian mitochondria kinetically behave as a single unit with control coefficients approaching unity for each component, suggesting the existence of substrate channeling within the super-complex. The formation of this supramolecular unit largely depends on the lipid content and composition of the inner mitochondrial membrane. The function of the super-complexes appears not to be restricted to kinetic advantages in electron transfer: we discuss evidence on their role in the stability and assembly of the individual complexes, particularly Complex I, and in preventing excess oxygen radical formation. There is increasing evidence that disruption of the super-complex organization leads to functional derangements responsible for pathological changes, as we have found in K-ras-transformed fibroblasts. 相似文献
68.
Stanzione F Esposito L Paladino A Pedone C Morelli G Vitagliano L 《Biophysical journal》2010,99(7):2273-2278
Neurotrophins (NTs) represent a family of proteins that play an important role in the survival, development, and function of neurons. Extensive efforts are currently being made to develop small molecules endowed with agonist or antagonist NT activity. The structurally versatile N-termini of these proteins are considered regions of interest for the design of new molecules. By combining experimental and computational approaches, we analyzed the intrinsic conformational preferences of the N-termini of two of the most important NTs: NGF (NGF-Nter) and NT4 (NT4-Nter). Circular dichroism spectra clearly indicate that both peptides show a preference for random coil states. Because this finding does not preclude the possibility that structured forms may occur in solution as minor conformational states, we performed molecular-dynamics simulations to gain insights into the structural features of populated species. In line with the circular dichroism analysis, the simulations show a preference for unstructured states for both peptides. However, the simulations also show that for NT4-Nter, and to a lesser extent for NGF-Nter, helical conformations, which are required for binding to the Trk receptor, are present in the repertoire of structures that are intrinsically accessible to these peptides. Accordingly, molecular recognition of NTs by the Trk receptor is accomplished by the general mechanism known as population shift. These findings provide a structural rationale for the observed activity of synthetic peptides based on these NT regions. They also suggest strategies for the development of biologically active peptide-based compounds. 相似文献
69.
Background
Previous epidemiologic studies have examined the association of smoking with amyotrophic lateral sclerosis (ALS) incidence, but their results have been inconsistent. Moreover, limited information exists on the association between smoking and survival in ALS patients. We evaluated the association of smoking with ALS incidence and survival in a population-based cohort. 相似文献70.
Cappitelli F Toniolo L Sansonetti A Gulotta D Ranalli G Zanardini E Sorlini C 《Applied and environmental microbiology》2007,73(17):5671-5675
This study compares two cleaning methods, one involving an ammonium carbonate-EDTA mixture and the other involving the sulfate-reducing bacterium Desulfovibrio vulgaris subsp. vulgaris ATCC 29579, for the removal of black crust (containing gypsum) on marble of the Milan Cathedral (Italy). In contrast to the chemical cleaning method, the biological procedure resulted in more homogeneous removal of the surface deposits and preserved the patina noble under the black crust. Whereas both of the treatments converted gypsum to calcite, allowing consolidation, the chemical treatment also formed undesirable sodium sulfate. 相似文献