Applications of homemade kit in mutation detection of genes

With the accomplishment of Human Genome Project (HGP), single nucleotide polymorphism (SNP) and mutation detection in human genome are becom-ing a new researching focus. These researches can help us to understand the phenotype diversity of indi-vidual, disease susceptibility and drug resistance of different colonies. Traditional method used for muta-tion detection is slab gel electrophoresis, which re-mains labor-intensive and time-consuming because of the requirement of radioactivity or te…     

A highly sensitive assay for protein using resonance light-scattering technique with dibromohydroxyphenylfluorone-molybdenum(VI) complex

At pH 2.8 and in the presence of 0.090% p-octylpolyethyleneglycol phenylether, the resonance light-scattering (RLS) spectrum of molybdenum(VI) complex with dibromohydroxyphenylfluorone (DBHPF) has a sharp peak at 586 nm. If the micro protein coexists with Mo(VI) and DBHPF, the RLS intensity of the complex at 586 nm is significantly enhanced by protein due to the binding interaction between protein and DBHPF-Mo(VI) complex. Based on this a new assay for protein is described. The dynamic ranges for bovine and human serum albumins are both 0.05-0.75 mg l-1 with detection limits of 13 and 15 ng ml-1, respectively. Besides high sensitivity, the method is characterized by good reproducibility, rapidity of reaction, good stability of chemical system, commonality of spectrofluorometer, few coexisting substances, especially detergents. The determinations of diluted human serum and urine by this method give the results very close to these by the Coomassie brilliant blue G-250 colorimetry, with relative standard deviations of five duplicates of 1.8-2.5%.     

STABILITY OF POLY（N,N＇-METHYLENEBISACRYLAMIDE-co-4-VINYLPYRIDINE） MICROGEL DISPERSION AND ADJUSTMENT OF THE HYDROPHOBICITY IN THE MICROGELS

In the UV-Vis spectra of pure light-scattering systems, there is an exponential relationship between absorbance and wavelength （A = Kλ^-n）. Here, the exponent n is named as flocculation-coagulation parameter. In the present paper, the effects of different additives on the stability of poly（N,N＇-methylenebisacrylamide-co-4-vinylpyridine） （poly（Bis-co-4-VP）） microgel dispersion were studied in detail via this parameter. The results showed that the stability of the dispersion mainly comes from the ionization of pyridine groups, making the microgel positively charged on its surface. This was confirmed by the measurement of Zeta potential and the result of conductometric titration. The result of fluorescence analysis indicated that the hydrophobicity in the microgels is enhanced with the increase in total 4-VP unit content.     

Characterization of highly sulfated cyclodextrins

A class of highly sulfated cyclodextrins (HS-CDs) was developed for enantiomeric separation of chiral compounds by capillary electrophoresis (CE). The HS-CDs were produced by a facile single-step direct sulfation of cyclodextrin using sulfur trioxide-trimethylamine complex in dimethylformamide. Characterization of the HS-CDs by electrospray ionization mass spectrometry and by CE using a well-established indirect detection method indicated the species have very narrow heterogeneity in terms of degree of sulfation. Elemental analysis of the HS-alpha-, beta- and gamma-CDs showed that the average sulfate contents were 11, 12, and 13 per CD molecule, respectively. The 13C NMR of HS-CDs is consistent with the structural assignment of nearly complete sulfation at C-6 primary hydroxyl groups and partial sulfation at the C-2 secondary hydroxyls (>70%), while the C-3 hydroxyls remain unsubstituted. Enantiomeric separation by CE using the HS-CDs as chiral selectors showed that HS-alpha-, beta- and gamma-CDs complement each other by exhibiting different chiral selectivities, resulting in resolution of many chiral neutral, acidic and basic compounds of greatly varying structural features. The part of HS-CD that interacts with the guest molecule during complexation and, therefore, the receiving end of the cyclodextrin hydrophobic bucket was surrounded with largely regiospecifically substituted C-2 sulfates and intact C-3 hydroxyls, both at the equatorial positions. Such global regiospecific structural arrangement in HS-CDs provides differential diasteroisomeric complexation is proposed to be the principal contributing factor in the resolving racemates.     

Optical properties of ZnO and ZnO:In nanorods assembled by sol-gel method

Self-assembled zinc oxide (ZnO) and indium-doping zinc oxide (ZnO:In) nanorod thin films were synthesized on quartz substrates without catalyst in aqueous solution by sol-gel method. The samples were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), Raman-scattering spectroscopy, room-temperature photoluminescence (PL) spectra, and temperature-dependent PL spectra measurements. XRD and Raman spectra illustrated that there were no single In2O3 phase in ZnO lattice after indium doping. The PL spectra of ZnO showed a strong UV emission band located at 394 nm and a very weak visible emission associated with deep-level defects. Indium incorporation induced the shift of optical band gap, quenching of the near-band-edge photoluminescence and enhanced LO mode multiphonon resonant Raman scattering in ZnO crystals at different temperatures. Abnormal temperature dependence of UV emission integrated intensity of ZnO and ZnO:In samples is observed. The local state emission peak of ZnO:In samples at 3.37 eV is observed in low-temperature PL spectra. The near-band-edge emission peak at room temperature was a mixture of excitons and impurity-related transitions for both of two samples.     

Paranemic crossover DNA: a generalized Holliday structure with applications in nanotechnology

Paranemic crossover (PX) DNA is a four-stranded coaxial DNA complex containing a central dyad axis that relates two flanking parallel double helices. The strands are held together exclusively by Watson-Crick base pairing. The key feature of the structure is that the two adjacent parallel DNA double helices form crossovers at every point possible. Hence, reciprocal crossover points flank the central dyad axis at every major or minor groove separation. This motif has been modeled and characterized in an oligonucleotide system; a minor groove separation of five nucleotide pairs and major groove separations of six, seven, or eight nucleotide pairs produce stable PX DNA molecules; a major groove separation of 9 nucleotide pairs is possible at low concentrations. Every strand undergoes a crossover every helical repeat (11, 12, 13, or 14 nucleotides), but the structural period of each strand corresponds to two helical repeats (22, 24, 26, or 28 nucleotides). Nondenaturing gel electrophoresis shows that the molecules are stable, forming well-behaved complexes. PX DNA can be produced from closed dumbbells, demonstrating that the molecule is paranemic. Ferguson analysis indicates that the molecules are similar in shape to DNA double crossover molecules. Circular dichroism spectra are consistent with B-form DNA. Thermal transition profiles suggest a premelting transition in each of the molecules. Hydroxyl radical autofootprinting analysis confirms that there is a crossover point at each of the positions expected in the secondary structure. These molecules are generalized Holliday junctions.     

Molecular structure of 2,2,4,4,6,6-hexamethyl-1,3,5-trimethylenecyclohexane as determined by gas-phase electron diffraction

The molecular structure of 2,2,4,4,6,6-hexamethyl-1,3,5-trimethylenecyclohexane has been determined in the gas phase at a nozzle tip temperature of 340 K. The electron diffraction data were found to be consistent with a model where the cyclohexane ring adopts a distorted twist-boat conformation. The averaged geometrical parameters (r(g) and 90 degree angle (alpha)) obtained from least squares analysis are r(C=C) = 1.346(4) A, r(C-C)(ring) = 1.537(1) A, r(C-C)(Me) = 1.543(1) A, 90 degree angle C(6)C(1)C(2) = 117.5(11) degrees, 90 degree angle C(1)C(2)C(3) = 113.1(12) degrees, and 90 degree angle MeCMe = 108.2(13) degrees. The experimental results are consistent with the results from HF/6-311G(d) and MP2/6-311G(d) calculations where the distorted twist-boat form is found to be lower in energy than the chair form by 9.85 and 10.7 kcal/mol, respectively.     

Isolation of sesquiterpenoids from sponge Dysidea avara and chemical modification of avarol as potential antitumor agents

The marine sponge Dysidea avara contained avarol (1) and avarone (2). Avarol on acylation yielded 2',5'-O-dibenzoylavarol (3); 2,5'-O-(4-chlorobenzoyl)avarol (4); 2,5'-O-dicinnamoylavarol (5); 2,5'-O-(4-bromobenzoyl)avarol(6); 2',5'-O-dioctanoylavarol (7); 2',5'-O-(4-fluorobenzoyl)avarol (8) and diacetylavarol (9). The structural elucidation of all the compounds 1-9 have been done by spectral analysis. The cytotoxicity of these compounds were also determined and evaluated. Compounds 6 and 9 showed selective cytotoxicity against Hepa (human hepatoma) and KB cell lines respectively.     

CCR5 antagonists: 3-(pyrrolidin-1-yl)propionic acid analogues with potent anti-HIV activity

[reaction: see text] A novel approach to alpha,alpha-disubstituted-beta-amino acids (beta(2,2)-amino acids) was employed in the synthesis of a series of 3-(pyrrolidin-1-yl)propionic acids possessing high affinity for the CCR5 receptor and potent anti-HIV activity. The rat pharmacokinetics for these new analogues featured higher bioavailabilities and lower rates of clearance as compared to cyclopentane 1.     

Studies on the substrate specificity of Escherichia coli galactokinase

In vitro glycorandomization (IVG) technology is dependent upon the ability to rapidly synthesize sugar phosphates. Compared with chemical synthesis, enzymatic (kinase) routes to sugar phosphates would be attractive for this application. This work focuses upon the development of a high-throughput colorimetric galactokinase (GalK) assay and its application toward probing the substrate specificity and kinetic parameters of Escherichia coli GalK. The demonstrated dinitrosalicylic assay should also be generally applicable to a variety of sugar-processing enzymes. [reaction: see text]