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Ciprofloxacin induced an increment of reactive oxygen species in sensitive strains of Staphylococcus aureus leading to oxidative stress detected by chemiluminescence while resistant strains did not suffer such stress. Oxidation of lipids was performed by employing thiobarbituric acid reaction to detect the formation of the amplified intermediate between reactive species oxygen and cytoplasmic macromolecules, namely malondialdehyde (MDA). The sensitive strain presented higher peroxidation of lipids than the resistant strain. The oxidative consequence for DNA was investigated by means of bacteria incubation with ciprofloxacin and posterior extraction of DNA, which was studied by high performance liquid chromatography (HPLC). Sensitive S. aureus ATCC 29213 showed an increase of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) respect controls without antibiotic; there was evident increase of the ratio between 8-oxodG and deoxyguanosine (dG) as a consequence of oxidation of dG to 8-oxodG considered the major DNA marker of oxidative stress. The resistant strain showed low oxidation of DNA and the analysis of 8-oxodG/dG ratio indicated lesser formation of 8-oxodG than S. aureus ATCC 29213. 相似文献
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Mudge J Miller NA Khrebtukova I Lindquist IE May GD Huntley JJ Luo S Zhang L van Velkinburgh JC Farmer AD Lewis S Beavis WD Schilkey FD Virk SM Black CF Myers MK Mader LC Langley RJ Utsey JP Kim RW Roberts RC Khalsa SK Garcia M Ambriz-Griffith V Harlan R Czika W Martin S Wolfinger RD Perrone-Bizzozero NI Schroth GP Kingsmore SF 《PloS one》2008,3(11):e3625
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Summary This article presents some statistical methods for estimating the parameters of a population dynamics model for annual plants. The model takes account of reproduction, immigration, seed survival in a seed bank, and plant growth. The data consist of the number of plants in several developmental stages that were measured in a number of populations for a few consecutive years; they are incomplete since seeds could not be counted. It is assumed that there are no measurement errors or that measurement errors are binomial and not frequent. Some statistical methods are developed within the framework of estimating equations or Bayesian inference. These methods are applied to oilseed rape data. 相似文献
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Haley Marshall Murugappan Venkat Nang San Hti Lar Seng Jackson Cahn Douglas H. Juers 《Acta Crystallographica. Section D, Structural Biology》2012,68(1):69-81
Both crystallization and cryoprotection are often bottlenecks for high‐resolution X‐ray structure determination of macromolecules. Methylamine osmolytes are known stabilizers of protein structure. One such osmolyte, trimethylamine N‐oxide (TMAO), has seen occasional use as an additive to improve macromolecular crystal quality and has recently been shown to be an effective cryoprotective agent for low‐temperature data collection. Here, TMAO and the related osmolytes sarcosine and betaine are investigated as primary precipitating agents for protein crystal growth. Crystallization experiments were undertaken with 14 proteins. Using TMAO, seven proteins crystallized in a total of 13 crystal forms, including a new tetragonal crystal form of trypsin. The crystals diffracted well, and eight of the 13 crystal forms could be effectively cryocooled as grown with TMAO as an in situ cryoprotective agent. Sarcosine and betaine produced crystals of four and two of the 14 proteins, respectively. In addition to TMAO, sarcosine and betaine were effective post‐crystallization cryoprotective agents for two different crystal forms of thermolysin. Precipitation reactions of TMAO with several transition‐metal ions (Fe3+, Co2+, Cu2+ and Zn2+) did not occur with sarcosine or betaine and were inhibited for TMAO at lower pH. Structures of proteins from TMAO‐grown crystals and from crystals soaked in TMAO, sarcosine or betaine were determined, showing osmolyte binding in five of the 12 crystals tested. When an osmolyte was shown to bind, it did so near the protein surface, interacting with water molecules, side chains and backbone atoms, often at crystal contacts. 相似文献
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Oluwatosin Adekeye Kim Ozano Ruth Dixon Elisabeth Osim Elhassan Luret Lar Elena Schmidt Sunday Isiyaku Okefu Okoko Rachael Thomson Sally Theobald Laura Dean 《PLoS neglected tropical diseases》2020,14(11)
Nigeria has the highest burden of NTDs in sub-Saharan Africa. Commitments to reach the control and elimination of many Neglected Tropical Diseases (NTDs), particularly those amenable to preventive chemotherapy (onchocerciasis, schistosomiasis, soil transmitted helminths, lymphatic filariasis and trachoma) by 2020 are detailed in the London declaration. Strategies to reach targets build on existing approaches, one of which is the use of community directed intervention (CDI) methods to deliver the mass administration of medicines (MAM). However, treatment using this approach has been inconsistent and there are questions about the acceptability and adaptability of these interventions during periods of programmatic, social, and political change. This paper explores the current strengths and weaknesses of CDI approaches in MAM delivery. We consider the acceptability and adaptability of existing MAM approaches to ensure equity in access to essential treatments. Using qualitative methods, we explore implementer perspectives of MAM delivery. We purposively selected programme implementers to ensure good programmatic knowledge and representation from the different levels of health governance in Nigeria. Data collection took place across two States (Kaduna and Ogun). Our results indicate that CDI approaches have underpinned many historic successes in NTD programme acceptance in Nigeria, specifically in Kaduna and Ogun State. However, our results also show that in some contexts, factors that underpin the success of CDI have become disrupted presenting new challenges for programme implementers. Capturing the tacit knowledge of health implementers at varying levels of the health system, we present the current and changing context of MAM delivery in Kaduna and Ogun States and consolidate a platform of evidence to guide future programme delivery and research studies. We situate our findings within the broader NTD literature, specifically, in identifying how our findings align to existing reviews focused on factors that shape individual acceptance of MAM. 相似文献
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Narci Romain Delattre Maud Larédo Catherine Vergu Elisabeta 《Journal of mathematical biology》2022,84(4):1-31
Journal of Mathematical Biology - Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection worldwide, resulting in approximately sixty thousand annual... 相似文献
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V. V. Kolpakov T. V. Bespalova E. A. Tomilova T. E. Shtork E. V. Mamchits N. Yu. Lar’kina A. A. Tkachuk 《Human physiology》2011,37(6):738-749
Statistical analysis of the distribution of the mean somatometric, functional, and psychophysiological parameters in the total sample of subjects with the use of the χ2 and λ tests and low, medium, and high habitual physical activity (HPA) levels (LHPA, MHPA, and HHPA, respectively) at different ontogenetic stages (junior and senior school students and young adults of both sexes) showed wide quantitative and qualitative ranges of psychophysiological individuality in a healthy population and demonstrated that it is reasonable to distinguish three typological groups or functional constitutional types (FT-1 corresponding to LHPA; FT-2, to MHPA; and FT-3, to HHPA). Typical first- and second-order parameters, as well as the results of third-order tests characterizing the current state, were determined for each FT. In order to comprehensively assess the constitutional type (synthetic constitution) of the subjects with low, medium, and high HPAs, the integrated analysis of the set of their characteristics was performed using the principles of polythetic (multi-variate) classification. The results obtained using multivariate statistical methods confirmed the basic postulate of the concept of typological variability of physiological individuality that a healthy human population is qualitatively heterogeneous in morphological, functional, and psychophysiological traits. The integrated physiological and statistical analyses of the results provided a scientific basis for three functional constitutional types (FT-1, FT-2, and FT-3) corresponding to three synthetic constitutional types (C 0-1, C 00, and C 01). These data indicate that the systemic (constitutional) approach to the estimation of individual typological characteristics confirm a high informativeness of partial constitution (FT-1, FT-2, and FT-3) in the human biological organization, and the set of characters selected for analysis allows the synthetic constitutional types to be adequately differentiated on a formal basis. 相似文献
9.
Correlation between pectate lyase activity and ability of diazotrophic Klebsiella oxytoca VN 13 to penetrate into plant tissues 总被引:2,自引:0,他引:2
Kovtunovych G. Lar O. Kamalova S. Kordyum V. Kleiner D. Kozyrovska N. 《Plant and Soil》1999,215(1):1-6
Diazotrophic Klebsiella oxytoca VN 13 was able to lyse pectate, but the lytic activity of cultures grown on non-selective
media was weak, and the enzyme was located mainly inside the cells. A small fraction of the population (10-6 to 10-5) was able to grow in a selective medium with sodium polygalacturonate as sole carbon source, and produced increased amounts
of the pectinolytic enzyme pectate lyase. When wheat seeds were inoculated with these bacteria, increased levels of this enzyme
correlated with a higher rate of internal colonization of wheat roots and with stimulation of wheat growth resulting in higher
biomass. This suggests that colonization occurs via lyzed pectin layers.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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V. V. Kolpakov T. V. Bespalova N. Yu. Lar’kina K. A. Lebedeva E. A. Tomilova T. F. Belova 《Human physiology》2009,35(5):600-611
Results of longitudinal studies were used to estimate the psychophysiological characteristics of preschool and young school
children and young adults of both sexes belonging to functional types (FTs) with low, medium, and high habitual physical activity
(HPA) levels (FT-1, LHPA; FT-2, MHPA, and FT-3, HHPA, respectively). Statistical analysis of the distributions of averaged
psychophysiological parameters in the total sample with the use of the χ2 and λ tests showed wide quantitative and qualitative ranges of psychophysiological individuality in a healthy population
and demonstrated that it is reasonable to distinguish three typological groups (FT-1, FT-2, and FT-3). Typical first- and
second-order parameters, as well as the results of third-order tests characterizing the current state, were determined for
each FT. Determination of the psychophysiological characteristics of FT-1, FT-2, and FT-3 and their prevailing behavioral
tendencies makes it possible to differentiate between strategies of organism-environment interaction and estimate their advantages
and disadvantages. 相似文献