OBJECTIVETo find the patterns of the rDNA ITS sequence variation in Gentiana, and establish the molecular biological method for the identification of the four kinds wild Gentiana from different regions in Gansu.

METHODThe ITS gene fragments were PCR amplified and sequenced. The rDNA ITS regions were analyzed by means of the software of Clustal X, MEGA3.

RESULTThe Complete ITS sequence of G. macrophylla, G. straminea, G. dahurica and G. officinale was 800 bp. The sequences of ITS1, ITS2 and 5.8S were 290, 340, 170 bp, respectively. Phylogenetic tree based on ITS1 and ITS2 sequences data was constrcuted by Neighbor-joining method.

CONCLUSIONITS sequence could be as the evidence for the molecular authentication of Gentiana.

DNA, Plant ; chemistry ; DNA, Ribosomal ; chemistry ; DNA, Ribosomal Spacer ; chemistry ; Gentiana ; genetics ; Phylogeny

OBJECTIVETo establish a rapid and convenient method of DNA modification by bisulfite sodium for the detection of DNA methylation.

METHODSThrough increasing the bisulfite sodium concentration and the temperature of treatment, cutting down the modification time, besides using glassmilk to adsorb the DNA in the purification and recovery, to improve the methods of DNA modification. Efficiency of cytosine converted to thymine in MAGE-A3 gene and DAP-K gene fragments were analyzed by bisulfite sequencing PCR in order to evaluate the DNA modification effect among the improved method, traditional method and kit method.

RESULTSThe operating time of test was shortened to about 3 hours by the improved method; conversion rate of unmethylated cytosine to thymine was over 99%; compared with the traditional method and kit method, there was no significant difference (χ(2) = 0.0564, P > 0.05); the improved method was only for the unmethylated cytosine conversion modification, and there was no significant difference in process of methylated cytosine converted to thymine comparing with the traditional method (χ(2) = 0.0149, P > 0.05).

CONCLUSIONThe improved method has high efficiency of DNA modification and has no significant effect on excessive modification;meanwhile, it has many advantages such as time-saving and easy to operate etc.

Cytosine ; chemistry ; DNA ; chemistry ; DNA Methylation ; Polymerase Chain Reaction ; Sulfites ; chemistry ; Thymine ; chemistry

AIMThe interactions between diorganotin (IV) complexes of 1,3-dimethyl-4-acetyl-5-pyrazolone (HL1) and mono-nucleotides together with DNA near physiological condition were investigated.

METHODSThe mode of action of the diorganotin (IV) complexes with mononucleotides and DNA under different conditions and different times were investigated by high resolution NMR technology and UV spectra.

RESULTSThe interaction of [(L1)2SnEt2] with AMP was shown to result in significant change of chemical shift of H(8), H(2) and 31P of AMP. Hyperchromic effect of DNA could be observed due to the interaction of; [(L1)2SnEt2] with DNA, while interaction of [(L1)2SnMe2] with AMP and DNA could only cause obvious change of chemical shift of 31P and lead to hypochromic effect of DNA.

CONCLUSIONThe results indicate that [(L1)2SnEt2] can selectively bind to the N1 atom of the base and the phosphate oxygen atom of AMP and may further destroy the helical structure of DNA, while the dimethyltin (IV) compound of 1,3-dimethyl-4-acetyl-5-pyrazolone [(L1)2SnMe2] merely binds to the the phosphate oxygen atom of AMP and causes the contraction of DNA helical structure.

Antineoplastic Agents ; chemistry ; DNA ; chemistry ; Nucleotides ; chemistry ; Organotin Compounds ; chemistry ; Porphyrins ; chemistry

Topoisomerases are nuclear enzymes that regulate the overwinding or underwinding of DNA helix during replication, transcription, recombination, repair, and chromatin remodeling. These enzymes perform topological transformations by providing a transient DNA break, through which the unique problems of DNA entanglement that occur owing to unwinding and rewinding of the DNA helix can be resolved. In mammals, topoisomerases are classified into two types, type I topoisomerase (Top1) and type II topoisomerase (Top2), depending on the number of strands cut in one round of action. Top1 induces single-strand breaks in DNA, and Top2 induces double-strand breaks. In cells from vertebrate species, there are two forms of Top2, designated alpha and beta. Top2α is involved in the cellular proliferation and pluripotency, while Top2β plays key roles in neurodevelopment. In this review, we cover recent advances in structural, mechanistic and functional insights into Top2.
Animals ; Cell Proliferation ; DNA Replication ; DNA Topoisomerases, Type II ; chemistry

DNA with different length was solved into ultra-pure water, the conducing behavior of the suspension was investigated at varied temperature and DNA concentration. The electrical conductivity of the samples increased with the increment of temperature and concentration of the solution. In terms of the length, the short-strand DNA (less than 50bp) showed a better conducting capability than the long-strand DNA(more than 1000bp). The electrical conductivity of short-strand DNA arrives at 1.08 x 10(-3) S/cm at room temperature. The conductance of the two DNA samples became similar at high temperature as well as their uptrend when DNA samples were heated.
DNA ; chemistry ; Electric Conductivity ; Solutions ; Temperature

To elucidate further sequence selectivity and nature of the binding of anticancer drugs to DNA, the interaction between anticancer drugs, which are minor groove ligands (distamycin A, DM and netropsin, NP) and intercalator (mitoxantrone, MT), and DNA were studied by electrospray ionization mass spectrometry. The 2 : 1 specific complex of DM and AT-rich DNA were observed principally, while only 1 : 1 specific complex of NP and AT-rich DNA were observed. MT specifically binds to GC-rich DNA. In addition, DM binds to DNA containing 5 A/T bases minor groove almost in a 2 : 1 mode and does not bind to DNA containing 3 A/T bases minor groove. NP binds most strongly to DNA containing 4 A/T bases minor groove. The 1 : 1 specific complex of MT and 6-mer DNA was also observed. The result of competitive binding experiment shows that DM binds more strongly to AT-rich DNA than NP does. These results provide bases for investigating the mechanism of interaction between the drugs and DNA and for improving the structure of target drug.
Antineoplastic Agents ; chemistry ; DNA ; chemistry ; Spectrometry, Mass, Electrospray Ionization ; methods

With the emergence of DNA nanotechnology in the 1980s, self-assembled DNA nanostructures have attracted considerable attention worldwide due to their inherent biocompatibility, unsurpassed programmability, and versatile functions. Especially promising nanostructures are tetrahedral framework nucleic acids (tFNAs), first proposed by Turberfield with the use of a one-step annealing approach. Benefiting from their various merits, such as simple synthesis, high reproducibility, structural stability, cellular internalization, tissue permeability, and editable functionality, tFNAs have been widely applied in the biomedical field as three-dimensional DNA nanomaterials. Surprisingly, tFNAs exhibit positive effects on cellular biological behaviors and tissue regeneration, which may be used to treat inflammatory and degenerative diseases. According to their intended application and carrying capacity, tFNAs could carry functional nucleic acids or therapeutic molecules through extended sequences, sticky-end hybridization, intercalation, and encapsulation based on the Watson and Crick principle. Additionally, dynamic tFNAs also have potential applications in controlled and targeted therapies. This review summarized the latest progress in pure/modified/dynamic tFNAs and demonstrated their regenerative medicine applications. These applications include promoting the regeneration of the bone, cartilage, nerve, skin, vasculature, or muscle and treating diseases such as bone defects, neurological disorders, joint-related inflammatory diseases, periodontitis, and immune diseases.
Nucleic Acids/chemistry* ; Regenerative Medicine ; Consensus ; Reproducibility of Results ; DNA/chemistry*

Self-assembled lipid films provide new insights into the structure-function relationships of biomolecules at the molecular level. It has potential applications in biology and bionics. In this paper, with regard to atomic force microscopy (AFM) characterization, the surface structures and growth kinetics of self-assembled lipid films as well as their applications in high-resolution AFM imaging of surface-immobilized biomolecules such as proteins, DNA and enzymes are reviewed.
DNA ; chemistry ; Humans ; Lipid Bilayers ; chemistry ; Microscopy, Atomic Force ; methods ; Phospholipids ; chemistry ; Proteins ; chemistry

Comparing to Chitosan, Chitosan-oligosaccharides have several special functions, such as water-soluble, antitumor activity, immunostimulating effects, and antimicrobial activity. The chitosan-oligosaccharide, the molecular weight of which was about 5000, was used as research model. According to the agarose gel electrophoresis and UV spectrophotometer it was proved that electrostatic interaction was playing a very important role in the formation process of chitosan-oligosaccharide/DNA complex. The potential of adsorbing DNA on chitosan-oligosaccharide was analyzed by gel electrophoresis and UV spectrophotometer, and it was indicated that chitosan-oligosaccharide can improve the storage and structure stability of DNA. To check its protection ability to DNA by DNase I digestive experiment, the result showed that chitosan-oligosaccharide could load with plasmid effectively and protect DNA from being digested by DNase I. It was proved that chitosan-oligosacchide was safe and effective for gene delivery and will have a very good future in the field of gene therapy.
Chitosan ; chemistry ; DNA ; chemistry ; Gene Transfer Techniques ; Genetic Vectors ; Nanoparticles ; chemistry ; Oligosaccharides ; chemistry

OBJECTIVETo evaluate the impact of surface modification on the DNA-binding ability of nano-hydroxyapatite (nHA).

METHODSChemical co-precipitation-hydrothermal synthesis was utilized to prepare the nHA particles, and polyethylenimine (PEI) was used for surface modification of the nHA. Transmission electron microscopic (TEM) observation and zeta potential detection of the nHA were carried out before and after surface modification. The abilities of the nanoparticles, at different pH values and different concentrations, for DNA-binding and DNA protection against nuclease digestion were assessed before and after surface modification by electrophoresis.

RESULTSTEM observation showed a short rod-like morphology of PEI-modified nHA with uniform particle size and good dispersion; the nHA without the modification tended to aggregate with poor dispersion. With a positive zeta potential, the PEI-modified nHA showed an obviously enhanced ability of DNA binding at different pH values and concentrations, with strong capacity to protect the DNA against Dnase I digestion. At the concentration of 250 µg/ml and a pH value of 7.0, the nHA-PEI showed an optimal efficiency of DNA-binding and DNA protection.

CONCLUSIONnHA with surface modification by PEI can serve as an effective vector for DNA binding and transfer.

Amino Acid Motifs ; DNA ; chemistry ; Durapatite ; chemistry ; Gene Transfer Techniques ; Genetic Vectors ; Nanoparticles ; chemistry ; Polyethyleneimine ; chemistry