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The soil bacterium Bacillus polymyxa is shown to effectively remove organic flotation collectors such as dodecyl amine, diamine, sodium isopropyl xanthate, and sodium oleate from alkaline solutions. Adsorption and bacterial growth studies indicated enhanced surface affinity of the amine collectors toward the bacterial cells. All the above organic reagents could be efficiently removed from alkaline solutions through bacterial interaction. Ultraviolet (UV)-visible and Fourier transform infrared (FTIR) spectra during biodegradation of these reagents revealed the stages in biodegradation. Possible mechanisms are outlined. 相似文献
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Background
Rates of molecular evolution in different lineages can vary widely, and some of this variation might be predictable from aspects of species' biology. Investigating such predictable rate variation can help us to understand the causes of molecular evolution, and could also help to improve molecular dating methods. Here we present a comprehensive study of the life history correlates of substitution rate variation across the mammals, comparing results for mitochondrial and nuclear loci, and for synonymous and non-synonymous sites. We use phylogenetic comparative methods, refined to take into account the special nature of substitution rate data. Particular attention is paid to the widespread correlations between the components of mammalian life history, which can complicate the interpretation of results. 相似文献249.
A simple method to analyze media consumption and by-product build-up in high-cell-density perfusion cultures has been developed. This technique makes use of media replenishment strategy which can be used to decouple the two phenomena. Also, the replenished media method can be used to identify limitation by complex and undefined media components such as bovine serum. 相似文献
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Tiwari Vaibhav Tiwari Kavindra Nath Singh Brahma Deo 《Plant Cell, Tissue and Organ Culture》2001,66(1):9-16
A mass in vitro propagation system for Bacopa monniera (L.) Wettst. (Scrophulariaceae), a medicinally important plant, has been developed. A range of cytokinins have been investigated
for multiple shoot induction with node, internode and leaf explants. Of the four cytokinins (6-benzyladenine, thidiazuron,
kinetin and 2-isopentenyladenine) tested thidiazuron (6.8 μM) and 6-benzyladenine (8.9 μM) proved superior to other treatments. Optimum adventitious shoot buds induction occurred at 6.8 μM thidiazuron where an average of 93 shoot buds were produced in leaf explants after 7 weeks of incubation. However, subculture
of leaf explants on medium containing 2.2 μM benzyladenine yielded a higher number (129.1) of adventitious shoot buds by the end of third subculture. The percentage
shoot multiplication (100%) as well as the number of shoots per explant remained the high during the first 3 subculture cycles,
facilitating their simultaneous harvest for rooting. In vitro derived shoots were elongated on growth regulator-free MS medium and exhibited better rooting response on medium containing
4.9 μM IBA. After a hardening phase of 3 weeks, there was an almost 100% transplantation success in the field.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献