Importantly, the emission intensity displayed a gradual decrease by adding spm into the above solution Figure 6 and Figure S23 Supporting Information. By calculating the displacement rate, 1. These results further demonstrate that the competitive binding takes place directly in this system. Study of supramolecular interactions between small molecules.
The precise control of DNA structures can help researchers investigate some important biological processes. Our supramolecular strategy is advantageous over other approaches that the transition process could be controlled without adjusting the pH to basic or acidic values.
Interactions between spm and DNA can be readily manipulated utilizing supramolecular competition between spm and AM for binding to CB7. The changes in states of spm resulted in the reversible switching of DNA between different forms.
In the current study, the CD was used as a reference technique to evidence DNA conformational changes. Moreover, the glycosidic conformation was identified by NOESY experiment on the basis of spatial connectivities between protons coupled by dipolar interaction. In this context also, it can serve as an interesting starting point for future researchers looking to finish full NMR structural study. Since polyamines are widely dispersed in the cell, the current study further provides new and valuable insight into reversible and accurate control of DNA helical structure in vivo.
Whether such a strategy is operative in vivo is yet to be understood. We believe that this approach offers a general and facile way toward reversible and accurate control of DNA helical structure. The compound CB7 was synthesized according to the previous literatures. All samples were measured in a quartz cell of 1 cm optical path length. The bandwidth was 5 nm and the response time was 2 s.
The desired spm concentration was obtained by adding appropriate amounts of stock solution, and the mixture was incubated for 15 min at room temperature. Subsequently, the CD spectra were determined and compared to a blank solution.
The starting sample was prepared in the desired buffer containing DNA and spm at desired concentrations. After a 15 min incubation at room temperature, CB7 was added sequentially to the starting preparation prior to measurement of CD spectra. The starting system was prepared in the desired buffer containing DNA, spm, and CB7 at desired concentrations. The following procedure was similar to the above one wherein AM was added sequentially to the starting preparation prior to measurement of CD spectra. The spectra were acquired with a 2 s relaxation delay and 32 transients using watergate pulse sequence with gradients W5 for water suppression.
The MestReNova program was used to process 1D spectra obtained from the original data. The signal assignments were based on the chemical shifts and intensity patterns. Thermal Stability and Reversibility Study: The DNA samples were prepared under the conditions of the experiment shown. The CD melting profiles were recorded using a heating rate of 0. The fluorescent emission spectra area: The plot of emission nm was recorded as a function of the concentration of CB7 added.
The following procedure was similar to the above one wherein spm was added sequentially to the starting preparation prior to fluorescence measurement. The plot of emission nm was recorded as a function of the concentration of spm added. National Center for Biotechnology Information , U. No authors declared any potential conflicts of interest. The funding organizations played no role in the design of study, choice of enrolled patients, review and interpretation of data, or preparation or approval of manuscript.
Skip to main content. Other Book, Software, and Website Reviews. DNA from A to Z. Book, Software, and Web Site Reviews. Clin Chem ; Holland and Daniel H. Jump to section Article Acknowledgments References. Jim DeLeo, Alan T. William Moore, Gerald L. Bicknell, and Melanie Swan. Show more Book, Software, and Website Reviews. Nodes are recognized as strongly, moderately or weakly supported with: Conflicting nodes discerned upon visual inspection were used as constraints with the other data set: Well-supported clades are highlighted by grey rectangles with roman numbers, of which incongruent clades are further emphasized with numbers in white.
These were assigned to 18 species including C. We performed two independent runs of 10 million generations of the Monte Carlo Markov chains, sampling every generations. Convergence of the stationary distribution was checked by visual inspection of plotted posterior estimates using Tracer v.
After discarding the first trees as burn-in, the samples were summarized in the maximum clade credibility tree using TreeAnnotator v.
The results were visualized using FigTree v. Ancestral state reconstruction was applied to assess the polarity of growth habit evolution in Callitriche among the three types of habit: The ecological characters were observed in the field or scored by retrieving label information from herbarium specimens used for molecular analyses or compiled from literature Fassett, ; Mason, ; Aston, ; Cook, ; Lansdown, , ; Bean, Hippuris was recognized as amphibious Cook, Trait history was inferred based on two sample sets: We pruned the far-related outgroup taxa using RASP v.
We traced evolution of the growth habit characters over the species trees of 20 in-group accessions or those and Hippuris using MP and ML approaches implemented in Mesquite v. For the ML reconstructions we employed the Markov k-state 1 Mk1 parameter model.
Reconstruction of historical biogeography was performed using RASP.
DNA from A to Z & Back Again is a romp through the past, present, and future of molecular diagnostics, personalized medicine, and genomics. This book's broad . DNA from A to Z & Back Again - Kindle edition by Carol A. Holland PhD MT ( ASCP), PhD, HCLD Daniel H. Farkas. Download it once and read it on your Kindle.
Given the trees with ambiguous topology, the following approaches that accept polytomies were used: The following seven biogeographic areas were defined, for each of which rough geographical data latitude and longitude are generated for BayArea: The species distributions were compiled from literature Fassett, ; Mason, ; Cook, ; Lansdown, , ; Bean, Occurrence records suspected to be aliens were omitted, for example C.
Biogeography was inferred based on two sample sets: We used the species trees of 20 in-group accessions or those and Hippuris generated for ancestral state reconstruction. Multiple ancestral states were allowed in both analyses. All other parameters were kept at the default settings. Sequences of the concatenated two plastid DNA regions of Callitriche consisting of 50 in-group and three outgroup samples resulted in an alignment with a total length of bp, of which characters were polymorphic and potentially parsimony-informative.
Therefore, only the BI tree is presented here Fig. Callitriche muelleri clade I and C. The latter clade was further divided into two strongly supported groups: Sequences of nrITS of Callitriche consisting of 50 in-group and three outgroup samples resulted in an alignment with a total length of bp. Four hundred and two characters were polymorphic, of which were potentially parsimony informative. The latter group was further divided into two clades: The species tree mostly resembles the topology of the plastid tree Fig. Clades are supported with 1. Clades equivalent to those in Figure 2 are given with roman numbers.
B Results of ancestral state reconstruction for Callitriche. Most likely states are given for major clades and shown in circle: States ambiguously inferred are as follows: C Results of biogeographic analyses for Callitriche. Most likely areas are given for major clades and that of interest and shown in circle those almost equally likely are separated by slashes: Bayesian binary method BBM reconstruction with outgroup left top ; BayArea reconstruction with outgroup right top ; BBM without outgroup left bottom ; BayArea without outgroup right bottom.
We inferred the ancestral state of growth habit in Callitriche in parsimony MP and likelihood ML frameworks.
An ML reconstruction with in-groups only estimated the ancestral state as terrestrial, whereas the results from an ML reconstruction including the most closely related outgroup Hippuris and MP reconstructions in both cases showed that terrestrial and amphibious were equally parsimonious or almost equally likely Fig. Various areas were suggested as the ancestral area: Arber, ; Sculthorpe, ; Cook, , or an amphibious lineage gave rise to both aquatic and terrestrial descendants.
We have obtained five terrestrial Callitriche spp. Brown Cook, ; C. Although the phylogenetic hypotheses based on plastid DNA and nrITS are partially in conflict see below Topological incongruences between plastid DNA and nrITS trees , the same or similar pattern at deeper nodes was recovered in both analyses, namely that C. The ancestral state reconstruction with in-groups only using ML support the terrestrial condition as the most likely ancestral state of Callitriche over an aquatic submerged and amphibious habit, whereas analyses including out-group and those employing MP failed to distinguish between scenarios Fig.
The remaining terrestrial species are distributed in different clades Fig.
Additional American terrestrial species probably belong to our clade VI including amphibious species from North and South America e. Thus, based on our current sampling, it is conclusive that a terrestrial habit is ancestral to an amphibious habit that evolved once and terrestrial species have evolved again from amphibious ancestors in three or four descendant lineages.
We do not expect changes in the inference with more complete sampling of extant species as discussed above, but such a higher likelihood of evolution of terrestrials from amphibious species than vice versa and a possibly biased extinction of early-branching amphibious and aquatic species in former times of aridification McKinney, indicate that our conclusion of a terrestrial ancestor of the genus could be misled by the analysis of extant species only. Callitriche is distributed widely around the world Lansdown, Based on dated phylogenetic trees for Plantaginaceae Bremer et al.
Haloragaceae; Chen et al. Petit Potamogetonaceae; Ito et al. Scrophulariaceae; Ito et al. We performed biogeographic analysis without molecular dating because 1 the phylogenetic trees remain unresolved see Fig. Our taxon sampling covers six Australasian taxa: Intercontinental dispersal in Callitriche certainly occurred several times as observed in clade VI, in which one accession of C. Considering the results of biogeographic inferences, which suggests North America as the ancestral area for these three species Fig.
Clade VII contains two additional species endemic to Australasia: The timing and direction in detail remain unclear due to the observed topological incongruences and the incomplete and slightly biased taxon sampling.