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331.
Ajit Rayamajhi Sam Nightingale Nisha Keshary Bhatta Rupa Singh Elizabeth Ledger Krishna Prasad Bista Penny Lewthwaite Chandeshwar Mahaseth Lance Turtle Jaimie Sue Robinson Sareen Elizabeth Galbraith Malgorzata Wnek Barbara Wilmot Johnson Brian Faragher Rachel Kneen Michael John Griffiths Tom Solomon 《PloS one》2015,10(8)
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Jayne E. Rattray Anirban Chakraborty Carmen Li Gretta Elizondo Nisha John Michelle Wong Jagoš R. Radović Thomas B. P. Oldenburg Casey R. J. Hubert 《Environmental microbiology》2021,23(3):1397-1406
Endospore-forming bacteria make up an important and numerically significant component of microbial communities in a range of settings including soils, industry, hospitals and marine sediments extending into the deep subsurface. Bacterial endospores are non-reproductive structures that protect DNA and improve cell survival during periods unfavourable for bacterial growth. An important determinant of endospores withstanding extreme environmental conditions is 2,6-pyridine dicarboxylic acid (i.e. dipicolinic acid, or DPA), which contributes heat resistance. This study presents an improved HPLC-fluorescence method for DPA quantification using a single 10-min run with pre-column Tb3+ chelation. Relative to existing DPA quantification methods, specific improvements pertain to sensitivity, detection limit and range, as well as the development of new free DPA and spore-specific DPA proxies. The method distinguishes DPA from intact and recently germinated spores, enabling responses to germinants in natural samples or experiments to be assessed in a new way. DPA-based endospore quantification depends on accurate spore-specific DPA contents, in particular, thermophilic spores are shown to have a higher DPA content, meaning that marine sediments with plentiful thermophilic spores may require spore number estimates to be revisited. This method has a wide range of potential applications for more accurately quantifying bacterial endospores in diverse environmental samples. 相似文献
333.
Summary A rapid shoot multiplication protocol was established for an important medicinal plant, Vitex negundo L., belonging to the family Verbenaceae, using Murashige and Skoog medium, achieved by shoot multiplication as well as callus regeneration. Shoot multiplication
was induced by different concentrations of 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea (TDZ), Benzyladenine and 6-furfuryl amino
purine separately along with 10% (v/v) coconut water. Green organogenetic callus was obtained by the combined effect of 0.5–2.15
μM TDZ and 1.7 μM indole-3-acetic acid (IAA) along with 1% polyvinylpyrrolidone (PVP), and produced the maximum number of shoots when subcultured
onto medium containing 2.7 μM TDZ alone. Elongation of in vitro shoots was observed in MS medium containing 2.4 μM gibberellic acid and rooting was induced by the combined effect of 1.71 μM IAA and 1.62 μM α-naphthalene acetic acid. 相似文献
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Rashmi Chaturvedi Kushagra Bansal Yeddula Narayana Nisha Kapoor Namineni Sukumar Shambhuprasad Kotresh Togarsimalemath Nagasuma Chandra Saurabh Mishra Parthasarathi Ajitkumar Beenu Joshi Vishwa Mohan Katoch Shripad A. Patil Kithiganahalli N. Balaji 《The Journal of biological chemistry》2010,285(40):30389-30403
339.
Microarrays are widely used for examining differential gene expression, identifying single nucleotide polymorphisms, and detecting methylation loci. Multiple testing methods in microarray data analysis aim at controlling both Type I and Type II error rates; however, real microarray data do not always fit their distribution assumptions. Smyth''s ubiquitous parametric method, for example, inadequately accommodates violations of normality assumptions, resulting in inflated Type I error rates. The Significance Analysis of Microarrays, another widely used microarray data analysis method, is based on a permutation test and is robust to non-normally distributed data; however, the Significance Analysis of Microarrays method fold change criteria are problematic, and can critically alter the conclusion of a study, as a result of compositional changes of the control data set in the analysis. We propose a novel approach, combining resampling with empirical Bayes methods: the Resampling-based empirical Bayes Methods. This approach not only reduces false discovery rates for non-normally distributed microarray data, but it is also impervious to fold change threshold since no control data set selection is needed. Through simulation studies, sensitivities, specificities, total rejections, and false discovery rates are compared across the Smyth''s parametric method, the Significance Analysis of Microarrays, and the Resampling-based empirical Bayes Methods. Differences in false discovery rates controls between each approach are illustrated through a preterm delivery methylation study. The results show that the Resampling-based empirical Bayes Methods offer significantly higher specificity and lower false discovery rates compared to Smyth''s parametric method when data are not normally distributed. The Resampling-based empirical Bayes Methods also offers higher statistical power than the Significance Analysis of Microarrays method when the proportion of significantly differentially expressed genes is large for both normally and non-normally distributed data. Finally, the Resampling-based empirical Bayes Methods are generalizable to next generation sequencing RNA-seq data analysis. 相似文献
340.
In this communication, a novel, green, efficient and economically viable light mediated protocol for generation of Au-nanoparticles using most vital organelle, chloroplasts, of the plant system is portrayed. Thylakoids/chloroplasts isolated from Potamogeton nodosus (an aquatic plant) and Spinacia oleracea (a terrestrial plant) turned Au3+ solutions purple in presence of light of 600 µmol m−2 s−1 photon flux density (PFD) and the purple coloration intensified with time. UV-Vis spectra of these purple colored solutions showed absorption peak at ∼545 nm which is known to arise due to surface plasmon oscillations specific to Au-nanoparticles. However, thylakoids/chloroplasts did not alter color of Au3+ solutions in dark. These results clearly demonstrated that photosynthetic electron transport can reduce Au3+ to Au0 which nucleate to form Au-nanoparticles in presence of light. Transmission electron microscopic studies revealed that Au-nanoparticles generated by light driven photosynthetic electron transport system of thylakoids/chloroplasts were in range of 5–20 nm. Selected area electron diffraction and powder X-ray diffraction indicated crystalline nature of these nanoparticles. Energy dispersive X-ray confirmed that these nanoparticles were composed of Au. To confirm the potential of light driven photosynthetic electron transport in generation of Au-nanoparticles, thylakoids/chloroplasts were tested for their efficacy to generate Au-nanoparticles in presence of light of PFD ranging from 60 to 600 µmol m−2 s−1. The capacity of thylakoids/chloroplasts to generate Au-nanoparticles increased remarkably with increase in PFD, which further clearly demonstrated potential of light driven photosynthetic electron transport in reduction of Au3+ to Au0 to form nanoparticles. The light driven donation of electrons to metal ions by thylakoids/chloroplasts can be exploited for large scale production of nanoparticles. 相似文献