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1.
Effects of Nitrogen Source and Bacterial Elicitor on Isoflavone Accumulation in Root Cultures of Albizzia kalkora (Roxb.) Prain 总被引:1,自引:0,他引:1
So-Young Park Wi-Young Lee Youngki Park Jin-Kwon Ahn 《植物学报(英文版)》2006,48(9):1108-1114
Changes in cellular isoflavone (daidzein and genistein) contents were monitored in root cultures of Albizzia kalkora (Roxb.) Prain after feeding different ratios of NH4^+/NO3^- and treatment with a biotic elicitor (three strains of Rhizobium sp.). The NH4^+/NO3^- ratio appears to be positively correlated with daidzein content in the roots and shows a negative correlation with genistein. Among the three different strains of Rhizobium used, the strain ATCC 15834 caused a 35% increase in daidzein production by infection. In the case of genistein, maximum production (94%) was obtained when cultures were treated on Day 6 by the strains ATCC 15834 and KCTC 1541. The biosynthetic pathway of the two isoflavones apparently reacts differently to the same culture conditions and the same strains of Rhizobium. Therefore, the present data suggest that the production of daidzein and genistein could be modulated by changing the NH4^+/NO3^- ratio and the application of Rhizobium. 相似文献
2.
Karla Cameron-Veas Marc Solà-Ginés Miguel A. Moreno Lorenzo Fraile Lourdes Migura-Garcia 《Applied and environmental microbiology》2015,81(5):1782-1787
The aim of this study was to evaluate if the treatments with ceftiofur and amoxicillin are risk factors for the emergence of cephalosporin resistant (CR) E. coli in a pig farm during the rearing period. One hundred 7-day-old piglets were divided into two groups, a control (n = 50) group and a group parenterally treated with ceftiofur (n = 50). During the fattening period, both groups were subdivided in two. A second treatment with amoxicillin was administered in feed to two of the four groups, as follows: group 1 (untreated, n = 20), group 2 (treated with amoxicillin, n = 26), group 3 (treated with ceftiofur, n = 20), and group 4 (treated with ceftiofur and amoxicillin, n = 26). During treatment with ceftiofur, fecal samples were collected before treatment (day 0) and at days 2, 7, 14, 21, and 42 posttreatment, whereas with amoxicillin, the sampling was extended 73 days posttreatment. CR E. coli bacteria were selected on MacConkey agar with ceftriaxone (1 mg/liter). Pulsed-field gel electrophoresis (PFGE), MICs of 14 antimicrobials, the presence of cephalosporin resistance genes, and replicon typing of plasmids were analyzed. Both treatments generated an increase in the prevalence of CR E. coli, which was statistically significant in the treated groups. Resistance diminished after treatment. A total of 47 CR E. coli isolates were recovered during the study period; of these, 15 contained blaCTX-M-1, 10 contained blaCTX-M-14, 4 contained blaCTX-M-9, 2 contained blaCTX-M-15, and 5 contained blaSHV-12. The treatment with ceftiofur and amoxicillin was associated with the emergence of CR E. coli during the course of the treatment. However, by the time of finishing, CR E. coli bacteria were not recovered from the animals. 相似文献
3.
Both habitat heterogeneity and species’ life-history traits play important roles in driving population dynamics, yet there is little scientific consensus around the combined effect of these two factors on populations in complex landscapes. Using a spatially explicit agent-based model, we explored how interactions between habitat spatial structure (defined here as the scale of spatial autocorrelation in habitat quality) and species life-history strategies (defined here by species environmental tolerance and movement capacity) affect population dynamics in spatially heterogeneous landscapes. We compared the responses of four hypothetical species with different life-history traits to four landscape scenarios differing in the scale of spatial autocorrelation in habitat quality. The results showed that the population size of all hypothetical species exhibited a substantial increase as the scale of spatial autocorrelation in habitat quality increased, yet the pattern of population increase was shaped by species’ movement capacity. The increasing scale of spatial autocorrelation in habitat quality promoted the resource share of individuals, but had little effect on the mean mortality rate of individuals. Species’ movement capacity also determined the proportion of individuals in high-quality cells as well as the proportion of individuals experiencing competition in response to increased spatial autocorrelation in habitat quality. Positive correlations between the resource share of individuals and the proportion of individuals experiencing competition indicate that large-scale spatial autocorrelation in habitat quality may mask the density-dependent effect on populations through increasing the resource share of individuals, especially for species with low mobility. These findings suggest that low-mobility species may be more sensitive to habitat spatial heterogeneity in spatially structured landscapes. In addition, localized movement in combination with spatial autocorrelation may increase the population size, despite increased density effects. 相似文献
4.
Matrix type transdermal films of donepezil (DNP) as an alternative delivery approach was designed to improve patient compliance to Alzheimer disease treatment. Sodium alginate, a natural polysaccharide, was used as matrix-forming agent in the optimization of transdermal films. Propylene glycol and dl-limonene was added into films as a plasticizer and permeation enhancer, respectively. As well as mechanical strength and bioadhesiveness of optimized transdermal films of DNP, the impact of dl-limonene concentration in films on DNP in vitro permeation across pig skin was assessed. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) measurements were carried out to examine the effects of enhancer on in vitro conformational order of the stratum corneum intercellular lipids following permeation study. Results showed that transdermal formulations of DNP were suitable due to both mechanical and bioadhesive features of the films. In vitro skin permeation study indicated that dl-limonene at a concentration of 3% was optimum with high drug flux. ATR-FTIR results confirmed a more fluidized stratum corneum lipid state in the presence of dl-limonene, indicating its permeation enhancement effect. Regarding to achieve therapeutic levels of DNP, it seems to be feasible deliver DNP with transdermal films for the management of Alzheimer disease.KEY WORDS: Alzheimer disease, donepezil, limonene, permeation enhancement, transdermal film 相似文献
5.
Marcos Amaku Marcelo Nascimento Burattini Francisco Antonio Bezerra Coutinho Eduardo Massad 《Bulletin of mathematical biology》2010,72(5):1294-1314
We consider two viral strains competing against each other within individual hosts (at cellular level) and at population level (for infecting hosts) by studying two cases. In the first case, the strains do not mutate into each other. In this case, we found that each individual in the population can be infected by only one strain and that co-existence in the population is possible only when the strain that has the greater basic intracellular reproduction number, R 0c , has the smaller population number R 0p . Treatment against the one strain shifts the population equilibrium toward the other strain in a complicated way (see Appendix B). In the second case, we assume that the strain that has the greater intracellular number R 0c can mutate into the other strain. In this case, individual hosts can be simultaneously infected by both strains (co-existence within the host). Treatment shifts the prevalence of the two strains within the hosts, depending on the mortality induced by the treatment, which is, in turn, dependent upon the doses given to each individual. The relative proportions of the strains at the population level, under treatment, depend both on the relative proportions within the hosts (which is determined by the dosage of treatment) and on the number of individuals treated per unit time, that is, the rate of treatment. Implications for cases of real diseases are briefly discussed. 相似文献
6.
Sébastien D. S. Pion Hugues C. Nana-Djeunga Joseph Kamgno Nicholas Tendongfor Samuel Wanji Flobert Njiokou Roger K. Prichard Michel Boussinesq 《PLoS neglected tropical diseases》2013,7(2)
Background/Objective
Ivermectin has been the keystone of onchocerciasis control for the last 25 years. Sub-optimal responses to the drug have been reported in Ghanaian communities under long-term treatment. We assessed, in two Cameroonian foci, whether the microfilaricidal and/or embryostatic effects of ivermectin on Onchocerca volvulus have been altered after several years of drug pressure.Methods
We compared the dynamics of O. volvulus skin microfilarial densities after ivermectin treatment in two cohorts with contrasting exposure to this drug: one received repeated treatment for 13 years whereas the other had no history of large-scale treatments (referred to as controls). Microfilarial densities were assessed 15, 80 and 180 days after ivermectin in 122 multiply treated and 127 ivermectin-naïve individuals. Comparisons were adjusted for individual factors related to microfilarial density: age and number of nodules.Findings
Two weeks post ivermectin, microfilarial density dropped equally (98% reduction) in the ivermectin-naïve and multiply treated groups. Between 15 and 180 days post ivermectin, the proportion of individuals with skin microfilariae doubled (from 30.8% to 67.8%) in controls and quadrupled (from 19.8% to 76.9%) in multiply treated individuals but the mean densities remained low in both sites. In fact, between 15 and 80 days, the repopulation rate was significantly higher in the multiply treated individuals than in the controls but no such difference was demonstrated when extending the follow-up to 180 days. The repopulation rate by microfilariae was associated with host factors: negatively with age and positively with the number of nodules.Conclusion
These observations may indicate that the worms from the multi-treated area recover mf productivity earlier but would be less productive than the worms from the ivermectin-naïve area between 80 and 180 days after ivermectin. Moreover, they do not support the operation of a strong cumulative effect of repeated treatments on the fecundity of female worms as previously described. 相似文献7.
Christoph Klein Juliane Betz Martin Hirschbuehl Caroline Fuchs Barbara Schmiedtová Martina Engelbrecht Julia Mueller-Paul Raphael Rosenberg 《PloS one》2014,9(12)
Ever since the Renaissance speaking about paintings has been a fundamental approach for beholders, especially experts. However, it is unclear whether and how speaking about art modifies the way we look at it and this was not yet empirically tested. The present study investigated to the best of our knowledge for the first time in what way speaking modifies the patterns of fixations and gaze movements while looking at paintings. Ninety nine university students looked at four paintings selected to cover different art historical typologies for periods of 15 minutes each while gaze movement data were recorded. After 10 minutes, the participants of the experimental group were asked open questions about the painting. Speaking dramatically reduced the duration of fixations and painting area covered by fixations while at the same time increasing the frequencies of fixations, gaze length and the amount of repeated transitions between fixation clusters. These results suggest that the production of texts as well-organised sequences of information, structures the gazes of art beholders by making them quicker, more focused and better connected. 相似文献
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Dehghanbanadaki Najme Taghdir Majid Naderi-Manesh Hossein 《International journal of peptide research and therapeutics》2021,27(1):353-363
International Journal of Peptide Research and Therapeutics - Wnt/β-catenin signaling, a highly evolutionary conserved pathway, is abnormally regulated in many human cancers. This pathway is... 相似文献
10.
Shabhat Rasool Ishfaq Ahmed Rubiya Dar Sheikh Gazalla Ayub Sabia Rashid Tariq Jan Tahir Ahmed Niyaz A. Naikoo Khurshid I. Andrabi 《Biochemical genetics》2013,51(3-4):323-333
This study looks at novel variants of the TGFβ1 gene and their potential association with high myopia in an ethnic population from Kashmir, India. Allele frequencies of 247 Kashmiri subjects (from India) with high myopia and 176 ethnically matched healthy controls were tested for Hardy–Weinberg disequilibrium. The genotype and allele frequencies were evaluated using chi-square or Fisher’s exact tests. One of the three SNPs in codon 10 showed a significant difference between patients and control subjects (rs1982073: p genotype = 0.003, p allele = 0.001). There were no statistically significant differences between patients and control subjects for the other two SNPs, rs1800471 at codon 25 and a novel variant at codon 52. SNP rs1982073, substituting proline with leucine, appeared to be significantly associated with high myopia (p < 0.05). In silico predictions show that substitutions are likely to have an impact on the structure and functional properties of the protein, making it imperative to understand their functional consequences in relation to high myopia. 相似文献
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Stéphanie Faure Agnès Perrin-Guyomard Jean-Michel Delmas Michel Laurentie 《Applied and environmental microbiology》2009,75(17):5523-5528
The conjugative transfer of the plasmid carrying the blaCTX-M-9 gene from Salmonella enterica serovar Virchow isolated from a chicken farm to a recipient Escherichia coli strain was evaluated in vitro and in axenic rats inoculated with both strains, with or without selective pressure due to therapeutic doses of cefixime. The transfer of the blaCTX-M-9 gene of S. enterica serovar Virchow to E. coli was confirmed in vitro, at a low frequency of 5.9 × 10−8 transconjugants/donors. This transfer rate was higher in gnotobiotic rats and reached ∼10−5 transconjugants/donors without selective pressure. This frequency was not affected by the addition of therapeutic doses of cefixime. Thus, estimates of in vitro transfer underestimated potential transfer in the digestive tract, and therapeutic doses of cefixime did not increase the selection for transconjugants.β-Lactams and extended-spectrum cephalosporins are widely used in human and veterinary medicine to treat severe infections in humans and animals caused by Enterobacteriaceae and other gram-negative pathogens (7). However, extended-spectrum β-lactamases (ESBLs) have emerged and become the major mechanism of resistance to β-lactam antibiotics. Until the late 1990s, TEM and SHV enzymes were the predominant ESBLs. However, over the last decade, CTX-M-type enzymes have become the most prevalent extended-spectrum β-lactamases worldwide. Currently, there have been a number of reports documenting an increasing prevalence of enteric pathogens that produce these plasmid-mediated CTX-M enzymes (4, 8, 9, 39).Although originally confined to hospitals, ESBL-producing strains are now emerging in the community. Several investigations have shown that the rate of fecal carriage of ESBL-positive isolates (especially Escherichia coli) in humans is increasing, with CTX-M type enzymes found in most isolates (14, 17, 25, 28, 30, 36). This alarming phenomenon may have serious economic consequences and implications for treatment.blaCTX-M genes spread throughout the community, mostly through the transmission of plasmids, and some studies have reported that animals may serve as a possible source for the dissemination of ESBL-encoding genes to humans. Indeed, common conjugative resistance plasmids and resistant clones have been found in animals, food products, and humans, suggesting that the transfer of extended-spectrum cephalosporin resistance between animals and humans is possible (17, 18, 21, 31, 40).In France, the emergence of the CTX-M-9 enzyme in Salmonella enterica serovar Virchow strains recovered from poultry, poultry products, and one human patient was reported between 2002 and 2003 (5, 31, 38, 40, 41). A comparative analysis of the blaCTX-M-2 and blaCTX-M-9 plasmids from S. enterica serovar Virchow isolates from human and poultry sources demonstrated a close relationship between the plasmids (16).To examine the hypothesis that antimicrobial resistance in humans could partly be attributed to food products, a number of studies have investigated the transfer of antibiotic resistance from bacteria originating in animal hosts or food products. Previously, Lester et al. (24) demonstrated the transfer of the vanA resistance gene from Enterococcus faecium isolated from animals to E. faecium isolated from human volunteers during transient intestinal colonization in humans in the absence of selective pressure. In a gnotobiotic mouse model, Feld et al. demonstrated the evidence of spread of a small plasmid pLFE1 harboring the erythromycin-resistant gene erm(B) from Lactobacillus plantarum isolated from raw-milk cheese to exogenous Enterococcus faecalis inoculated into the intestinal flora of mice (16). The transfer rate was enhanced when erythromycin was coadministered. Improvements in our understanding of the in vivo transmissibility and stability of antimicrobial resistance markers and the mechanisms driving horizontal transmission may help to predict the outcome of different strategies for controlling epidemic plasmids.The aim of the present study was to determine whether the blaCTX-M-9 resistance gene could be transferred from an animal S. enterica serovar Virchow strain to a commensal E. coli strain that originated from the human intestinal tract while under selective pressure from a therapeutic dose of β-lactam. The transfer was investigated by using in vitro mating and a germfree rat model. We also evaluated the impact of the concentration of cefixime, an expanded-spectrum cephalosporin, on the transfer rate. 相似文献
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chelators can modulate β-amyloid accumulation, protect against tau hyperphosphorylation, and block metal-related oxidative
stress, and thereby hold considerable promise as effective anti-AD drugs. At present, a growing interest is focusing on increasing
the efficacy and targeting of chelators through drug design. To this end, we have developed a new class of multifunctional
prochelators from three FDA- approved drugs rasagiline, rivastigmine, and donepezil or tacrine. HLA20 A was designed by merging the important pharmacophores of rasagiline, rivastigmine, and donepezil into our newly developed
multifunctional chelator HLA20. M30D was constructed using the key pharmacophoric moieties from rasagiline, rivastigmine, and tacrine. Experiments showed that
both compounds possess potent anti-acetylcholinesterase (AChE) activity in vitro with weak inhibition of butyrylcholinesterase
(BuChE), and without significant metal-binding activity. M30D was found also to be a highly potent MAO A inhibitor with moderate inhibition of MAO B in vitro. Both HLA20 and M30D can be activated by inhibition of AChE to release active chelators HLA20 and M30, respectively. HLA20 and M30 have been shown to be able to modulate amyloid precursor protein regulation and beta-amyloid reduction, suppress oxidative
stress, and passivate excess metal ions (Fe, Cu, and Zn). Compared with the activated chelator HLA20 or M30, both HLA20A and M30D exhibited lower cytotoxicity in SH-SY5Y neuroblastoma cells, substantiating the prochelator strategy for minimizing toxicity
associated with poor targeted chelators. 相似文献
16.
Robert Blue Jihong Li Jonathan Steinberger Marta Murcia Marta Filizola Barry S. Coller 《The Journal of biological chemistry》2010,285(23):17604-17613
Structural data of integrin αIIbβ3 have been interpreted as supporting a model in which: 1) the receptor exists primarily in a “bent,” low affinity conformation on unactivated platelets and 2) activation induces an extended, high affinity conformation prior to, or following, ligand binding. Previous studies found that “clasping” the αIIb head domain to the β3 tail decreased fibrinogen binding. To study the role of αIIb extension about the genu, we introduced a disulfide “clamp” between the αIIb thigh and calf-1 domains. Clamped αIIbβ3 had markedly reduced ability to bind the large soluble ligands fibrinogen and PAC-1 when activated with monoclonal antibody (mAb) PT25-2 but not when activated by Mn2+ or by coexpressing the clamped αIIb with a β3 subunit containing the activating mutation N339S. The clamp had little effect on the binding of the snake venom kistrin (Mr 7,500) or αIIbβ3-mediated adhesion to immobilized fibrinogen, but it did diminish the enhanced binding of mAb AP5 in the presence of kistrin. Collectively, our studies support a role for αIIb extension about the genu in the binding of ligands of 340,000 and 900,000 Mr with mAb-induced activation but indicate that it is not an absolute requirement. Our data are consistent with αIIb extension resulting in increased access to the ligand-binding site and/or facilitating the conformational change(s) in β3 that affect the intrinsic affinity of the binding pocket for ligand. 相似文献
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Summary The effects of 2deoxycoformycin, a specific inhibitor of adenosine deaminase, on the repair and fixation of potentially lethal damage (PLD) sensitive to treatment with-araA, an adenosine analogue acting via inhibition of DNA polymerases and, have been studied. Given after irradiation deoxycoformycin alone had little effect on cell survival. More damage was nevertheless fixed by a given concentration of-araA in the presence of deoxycoformycin to a degree that 35 µM-araA given simultaneously with 1 µg/ml deoxycoformycin produced the same effect (survival decrease to 20% of the controls) as 90 µM-araA given alone. Maximum potentiation of the-araA effect was observed at 1 µg/ml deoxycoformycin with a slight decrease at higher concentrations.Combined treatment with-araA and deoxycoformycin reduced or eliminated the shoulder from the survival curve without affecting the slope, an effect similar to that observed after treatment of cells with-araA alone. The results indicate the importance of adenosine deaminase in the inactivation of nucleoside analogues and are discussed vis-a-vis the possible practical application of this inhibitor in both experimental and therapeutic applications. 相似文献
18.
Objective
NI margins have to be chosen appropriately to control the risk of degradation of treatment effects in non-inferiority (NI) trials. We aimed to study whether the current choice of NI margins protects sufficiently against a degradation of treatment effect on an average.Study Design and Setting
NI trials reflecting current practice were assembled and for each trial, the NI margin was translated into a likelihood of degradation. The likelihood of degradation was calculated as the conditional probability of a treatment being harmful given that it is declared non-inferior in the trial, using simulation. Its distribution among the NI trials was then studied to assess the potential risk of degradation.Results
The median (lower/upper quartile) NI margin among 112 binary outcome NI trials corresponded to an odds ratio of 0.57(0.45, 0.66), while among 38 NI trials with continuous outcome, to a Cohen’s d of −0.42(−0.54, −0.31) and a hazard ratio of 0.82(0.73, 0.86) among 24 survival outcome NI trials. Overall, the median likelihood of degradation was 56% (45%, 62%).Conclusion
Only two fifths of the current NI trials had a likelihood of degradation lower than 50%, suggesting that, in majority of the NI trials, there is no sufficient protection against degradation on an average. We suggest a third hurdle for the choice of NI margins, thus contributing a sufficient degree of protection. 相似文献19.