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201.
202.
Christophe Morell André Grand Alejandro Toro-Labbé Henry Chermette 《Journal of molecular modeling》2013,19(7):2893-2900
In this work, the third derivative of the energy with respect to the number of electrons, the so-called hyper-hardness, is investigated to assess whether this quantity has a chemical meaning. To achieve this goal a new working expression for hyper-hardness is developed and analyzed. It transpired from this analysis that hyper-hardness, just like hardness, can measure the reactivity or the stability of electron systems. Interestingly, positive values of hyper-hardness point to quite stable species such as noble gases and molecules. On the other hand, radicals almost always display large negative values of hyper-hardness. 相似文献
203.
204.
Innominato PF Giacchetti S Moreau T Smaaland R Focan C Bjarnason GA Garufi C Iacobelli S Tampellini M Tumolo S Carvalho C Karaboué A Lévi F;ARTBC International Chronotherapy Group 《Chronobiology international》2011,28(7):586-600
Circadian clocks control cellular proliferation and drug metabolism over the 24?h. However, circadian chronomodulated chemotherapy with 5-fluorouracil, leucovorin, and oxaliplatin (chronoFLO4) offered no survival benefit as compared with the non-time-stipulated FOLFOX2, in an international randomized trial involving patients with previously untreated metastatic colorectal cancer (EORTC 05963). The authors hypothesized that treatment near maximum tolerated dose could disrupt circadian clocks thus impairing the efficacy of chronoFLO4 but not of FOLFOX2. Patients with available data (N?=?556) were categorized into three subgroups according to the worst grade (G) of neutropenia experienced during treatment. Distinct multivariate models with time-dependent covariates were constructed for each treatment schedule. Neutropenia incidence (all grades) was 33% on chronoFLO4 and 61% on FOLFOX2 (p?.0001), and G3-4 were 7% and 25%, respectively (p < .0001). Neutropenia was significantly more frequent in women than men on either schedule (FOLFOX2, p = .003; chronoFLO4, p = .04). Median survival was 20.7 mo in patients with G3-4 neutropenia versus 12.5 mo in neutropenia-free patients on FOLFOX2 (p < .0001). Corresponding figures were 13.7 and 19.4 mo, respectively, on chronoFLO4 (p?=?.36). Multivariate analysis confirmed occurrence of severe neutropenia independently predicted for better overall survival on FOLFOX2 (HR?=?0.56; p = .015), and worse survival on chronoFLO4 (HR?=?1.77, p = .06), with a significant interaction test (p < .0001). Prediction of better survival in neutropenic patients on FOLFOX2 supports the administration of conventional chemotherapy near maximum tolerated dose. The opposite trend shown here for chronoFLO4 supports the novel concept of jointly optimized hematologic tolerability and efficacy through personalized circadian-timed therapy. 相似文献
205.
Priscila da Silva Delabona Deise Juliana Lima Diogo Robl Sarita Cândida Rabelo Cristiane Sanchez Farinas José Geraldo da Cruz Pradella 《Journal of industrial microbiology & biotechnology》2016,43(5):617-626
The use of glycerol obtained as an intermediate of the biodiesel manufacturing process as carbon source for microbial growth is a potential alternative strategy for the production of enzymes and other high-value bioproducts. This work evaluates the production of cellulase enzymes using glycerol for high cell density growth of Trichoderma harzianum followed by induction with a cellulosic material. Firstly, the influence of the carbon source used in the pre-culture step was investigated in terms of total protein secretion and fungal morphology. Enzymatic productivity was then determined for cultivation strategies using different types and concentrations of carbon source, as well as different feeding procedures (batch and fed-batch). The best strategy for cellulase production was then further studied on a larger scale using a stirred tank bioreactor. The proposed strategy for cellulase production, using glycerol to achieve high cell density growth followed by induction with pretreated sugarcane bagasse, achieved enzymatic activities up to 2.27 ± 0.37 FPU/mL, 106.40 ± 8.87 IU/mL, and 9.04 ± 0.39 IU/mL of cellulase, xylanase, and β-glucosidase, respectively. These values were 2 times higher when compared to the control experiments using glucose instead of glycerol. This novel strategy proved to be a promising approach for improving cellulolytic enzymes production, and could potentially contribute to adding value to biomass within the biofuels sector. 相似文献
206.
Rodrigo Arreola José Luis Villalpando Jonathan Puente-Rivera Jorge Morales-Montor Enrique Rudiño-Piñera María Elizbeth Alvarez-Sánchez 《Molecular biotechnology》2018,60(8):563-575
Previously, metalloproteinase was isolated and identified from Trichomonas vaginalis, belonging to the aminopeptidase P-like metalloproteinase subfamily A/B, family M24 of clan MG, named TvMP50. The native and recombinant TvMP50 showed proteolytic activity, determined by gelatin zymogram, and a 50 kDa band, suggesting that TvMP50 is a monomeric active enzyme. This was an unexpected finding since other Xaa-Pro aminopeptidases/prolidases are active as a biological unit formed by dimers/tetramers. In this study, the evolutionary history of TvMP50 and the preliminary crystal structure of the recombinant enzyme determined at 3.4 Å resolution is reported. TvMP50 was shown to be a type of putative, eukaryotic, monomeric aminopeptidase P, and the crystallographic coordinates showed a monomer on a “pseudo-homodimer” array on the asymmetric unit that resembles the quaternary structure of the M24B dimeric family and suggests a homodimeric aminopeptidase P-like enzyme as a likely ancestor. Interestingly, TvMP50 had a modified N-terminal region compared with other Xaa-Pro aminopeptidases/prolidases with three-dimensional structures; however, the formation of the standard dimer is structurally unstable in aqueous solution, and a comparably reduced number of hydrogen bridges and lack of saline bridges were found between subunits A/B, which could explain why TvMP50 portrays monomeric functionality. Additionally, we found that the Parabasalia group contains two protein lineages with a “pita bread” fold; the ancestral monomeric group 1 was probably derived from an ancestral dimeric aminopeptidase P-type enzyme, and group 2 has a probable dimeric kind of ancestral eukaryotic prolidase lineage. The implications of such hypotheses are also presented. 相似文献
207.
Antonio J. Arenas Sebastian Napp Antonio Arenas-Montes Carmen Borge Alfonso Carbonero Anselmo Perea Rafael Cadenas Ignacio García-Bocanegra 《The Journal of wildlife management》2012,76(1):102-107
We carried out an experimental study to determine the serological response against myxoma virus (MV) and rabbit hemorrhagic disease virus (RHDV) in wild rabbits using commercial vaccines. Seroconversion against MV ranged between 72.7% and 97.2% in animals vaccinated by subcutaneous and intradermal route, respectively, whereas between 75.0% and 77.8% of the animals presented antibodies against RHDV after inoculation with subcutaneous and intradermal vaccines, respectively. Regardless of the inoculation route, vaccination against MV resulted in a significant increase of seropositivity 5 days post-vaccination (dpv), which did not occur in animals vaccinated against RHDV. Furthermore, seroconversion against MV was significantly higher and faster in intradermally vaccinated rabbits as compared to those inoculated subcutaneously due to either the route of application and/or the type of vaccine used. The results indicated that vaccination significantly increased the prevalence of antibodies against MV and RHDV and suggested that the vaccines currently available induce a safe and effective immune response against both diseases in wild rabbits. Vaccination may be a useful management tool to control both viral diseases in field conditions, particularly in wild rabbits captured for translocations and restocking purposes in which a large number of animals are handled. © 2011 The Wildlife Society. 相似文献
208.
209.
Karen?M. Reiser Alexander?B. McCourt Diego?R. Yankelevich André Knoesen 《Biophysical journal》2012,103(10):2177-2186
The molecular basis of nonlinear optical (NLO) chiral effects in the amide I region of type I collagen was investigated using sum-frequency generation vibrational spectroscopy; chiral and achiral tensor elements were separated using different input/output beam polarization conditions. Spectra were obtained from native rat tail tendon (RTT) collagen and from cholesteric liquid crystal-like (LC) type I collagen films. Although RTT and LC collagen both possess long-range order, LC collagen lacks the complex hierarchical organization of RTT collagen. Their spectra were compared to assess the role of such organization in NLO chirality. No significant differences were observed between RTT and LC with respect to chiral or achiral spectra. These findings suggest that amide I NLO chiral effects in type I collagen assemblies arise predominantly from the chiral organization of amide chromophores within individual collagen molecules, rather than from supramolecular structures. The study suggests that sum-frequency generation vibrational spectroscopy may be uniquely valuable in exploring fundamental aspects of chiral nonlinearity in complex macromolecular structures. 相似文献
210.
Here we describe the visualization by confocal microscopy of ingested gold (15nm)-labeled transferrin in epimastigote forms of the protozoan Trypanosoma cruzi. Intracellular gold labeling was evident at two sites, which represent the bottom of the cytopharynx and the reservosomes. The gold tracer was best observed by confocal microscopy by using the 633nm excitation wavelength. Intracellular gold clusters larger than 60nm could be visualized by either gold reflection (light scattering) or photoluminescence modes. The gold reflection mode, the gold photoluminescence mode and the anti-transferrin immunofluorescence image of gold-labeled transferrin showed co-localization, thus demonstrating that the gold visualization modes did not represent artifacts or mislocalization of the biomarker. Visualization of protein-gold nanoparticle complexes by confocal microscopy thus emerges as a promising imaging tool to explore the endocytic pathway in trypanosomes and other cell types, as well as to perform immunolocalization studies using gold-labeled secondary antibodies. 相似文献