Physicochemical properties of fowlpox virus deoxyribonucleic acid and its anomalous infectious behavior

Randall, Charles C. (University of Mississippi, Jackson), Lanelle G. Gafford, Richard L. Soehner, and James M. Hyde. Physicochemical properties of fowlpox virus deoxyribonucleic acid and its anomalous infectious behavior. J. Bacteriol. 91:95-100. 1966.-Deoxyribonucleic acid (DNA) was extracted from fowlpox virus-infected tissue, purified inclusions, and purified virus by five variations of detergent and phenol methods. Phenol methods gave a poor yield, whereas detergent techniques extracted up to 78% of the DNA. The buoyant density was 1.695 g/ml, and the melting temperature in 7.2 m NaClO(4) was 39 C, both approximately equivalent to a guanine plus cytosine content of 35 moles per cent. Further proof of the double-stranded nature of the DNA was shown by the characteristic behavior toward deoxyribonuclease, formaldehyde, and heat. Infectious DNA was obtained by the various methods described, but this manifestation of biological activity was capricious and for unknown reasons was often not evident. The infectivity could not be related quantitatively to the amount of DNA employed. Furthermore, the infectious nature of fowlpox virus DNA was demonstrable only when the route of infection was the chorioallantoic membrane. In contrast, whole virus infected both membrane and chick skin with equal efficiency.     

Physicochemical properties of Nebraska calf diarrhea virus hemagglutinin.

Highly purified Nebraska calf diarrhea virus (NCDV) was prepared by cesium chloride density gradient centrifugation. The effect of temperature, pH, different concentrations of formaldehyde, chloroform, ether, ethyl alcohol, and methyl alcohol on NCDV hemagglutinin and virus morphology was studied. NCDV hemagglutinin was inactivated by temperature, pH 2.0, chloroform, ethyl alcohol, and methyl alcohol.     

Physicochemical properties of T4 polynucleotide kinase.

Some physicochemical properties of T4 polynucleotide kinase (EC2.7.1.78) have been studied. The enzyme is an oligomer of one polypeptide chain. The molecular weight of the monomer is 33000, as determined from the amino acid analysis. Phenylalanine is the N-terminal amino acid. Each monomer contains two --SH groups, one exposed and one more buried. Circular dichroic spectra suggest a high content of alpha-helical structure, 45--55%. Excitation at 280 nm gave a strong emission fluorescence spectrum with a maximum centering at 340 nm. Sedimentation studies suggested the enzymically active form to be a tetramer. High ionic strength (0.1 M KC1), spermine, and the substrates ATP and thymidine 3'-monophosphate were found to be essential factors in order to stabilize the protein in an oligomeric structure. The association constants for ATP, thymidine 3'-monphosphate, and P1 were determined fluorimetrically to be 7.9 x 105, 4.8 x 105, and 7.2 x 10(2) M-1 respectively.     

Physicochemical properties of tipula iridescent virus

The molecular weight of Tipula iridescent virus, based on sedimentation and diffusion coefficients, was 5.51 × 10⁸, with hydration of 0.57 g of water per g of virus. Deoxyribonucleic acid content, based on total inorganic phosphorus liberated, was 19 ± 0.2%. At 260 mμ, the virus gave an uncorrected absorbance of 18.2 cm²/mg of virus and a light-scattering corrected absorbance of 9.8 cm²/mg of virus. Amino acid analyses of the virus protein revealed a remarkable similarity to Sericesthis iridescent virus. The possibility is discussed that the four iridescent insect viruses reported to date bear a strain relationship.     

Physicochemical properties of structured water in human albumin and gammaglobulin solutions.

The physicochemical properties of the different phases of water molecules were studied in concentrated solutions (132 g/L) of human serum albumin and gammaglobulin by (1)H NMR relaxometry. Spin-lattice (T1) relaxation times of total water and structured water (non-freezable water) were measured at 40 MHz above and below the freezing point of bulk water (ordinary, liquid water) at different temperatures. Analysis of the temperature dependence of the T1 demonstrated that total water differed qualitatively while structured water characteristics changed both quantitatively and qualitatively in the two protein solutions. Comparison of the temperature dependence of the structured water's T1 in the two solutions in the presence of an increasing concentration of manganese chloride allowed two main conclusions to be drawn. Firstly, the differences observed in total water and structured water physicochemical properties are directly related to protein structure and three-dimensional arrangement. Secondly, the motion of structured water determines the motion of the total water in the system through the values of the translational diffusion and chemical exchange correlation times tau(D) and tau m.     

Physicochemical properties of aqueous xanthan solutions: Static light scattering

The secondary structure of xanthan in solutions of relatively low salt concentration and at room temperature has been investigated using static light scattering experiments. Additional evidence has been found for a dimeric structure at 25°C in 0.01M NaCl. From the experimental z-average mean square (ms) radius of gyration, a value for the persistence length p has been estimated, taking explicitly into account the polydispersity of the three samples used, which has been established by gel permeation chromatography (GPC) measurements. The experimental particle scattering functions of the three samples are consistent with theoretical estimates for polydisperse systems with the same value of p = 65 ± 10 nm and the molar mass per unit length for a dimeric structure. This secondary structure remains unaffected by the ionic strength in the 0.005–0.0lM range. Partial aggregation seems to occur at higher NaCl concentrations. Light scattering and GPC data show that heating the xanthan 0.01M NaCl solutions to about 70°C considerably reduces the M_w of the low molar mass sample (2.3 × 10⁵-g·mol^?1), contrary to what is observed for the high molar mass sample (1.8 × 10⁶-g·mol^?1). These experimental findings can be accounted for by a partial temperature-induced dissociation of the xanthan dimers according to an all-or-none mechanism. © 1994 John Wiley & Sons, Inc.     

兔出血症病毒2型理化特性研究

[目的]本研究旨在研究该病毒的理化特性,评价不同处理条件对RHDV2的杀灭效果.[方法]本研究拟对临床疑似RHDV2感染致死的家兔进行RT-PCR鉴定病原,并利用不同pH值、不同温度、常用兽用消毒剂、不同浓度甲醛处理RHDV2,通过PMA-RT-qPCR对病毒理化特性进行研究.[结果]经RT-PCR检测与测序分析,确诊...     

Physicochemical properties of phosphorothioate oligodeoxynucleotides.

We have recently shown that phosphorothioate (PS) oligodeoxynucleotide (ODN) analogs, unlike their normal congeners, exhibit significant anti-HIV activity (Matsukura et al., (1987) Proc. Natl. Acad. Sci. USA 84, 7706-7710). We now report the syntheses, melting temperatures (Tm), and nuclease susceptibilities of a series of phosphorothioate ODN analogs. These include all-PS duplexes, duplexes with one normal chain and the other chain either all-PS, or end-capped with several PS groups at both 3' and 5' ends. The DNase susceptibilities of the S-ODNs are much less than the normal phosphodiesters, but by contrast duplexes of poly-rA with S-dT40 are much more susceptible to RNase H digestion. The Tm's for AT base pairs of S-ODNs are significantly depressed relative to normals, while GC base pairs show much less Tm depression. The Tm's of S-dT oligomers with poly-rA are reduced relative to the duplexes with normal dA oligomers. These results have significance for the biological properties of these analogs as anti-message inhibitors of gene expression, and provide a rational basis for the S-dC/G sequences as potential effective anti-AIDS agents.