Heterocycles from saccharide hydrazones : Part I. Saccharide 1,3,4-oxadiazoles

Oxidation, with iodine-mercuric oxide, of acetylated saccharide aroylhydrazones and of aromatic aldehyde hydrazones yields 5-aryl-2-(polyacetoxyalkyl)-1,3,4-oxadiazoles and 2,5-diaryl-1,3,4-oxadiazoles, respectively. On de-O-acetylation, saccharide oxadiazole acetates rearrange to the tautomeric, cyclic iminolactones which, on reacetylation, regenerate the starting oxadiazoles. Attempted dehydration of saccharide acetyl- and benzoyl-hydrazones by treatment with boiling acetic anhydride under reflux resulted in the formation of peracetylated N,N-diacetylhydrazones and-N-acetyl-N-benzoylhydrazones, respectively.     

Immobilization antigens of Tetrahymena pyriformis : I. Assay and extraction

A method using immunodiffusion has been established to assay the two mutually exclusive temperature dependent immobilization antigens, H and T, of Tetrahymena pyriformis. Specific antiserum was obtained by exploitation of allelic or temperature induced variations among inbred strains for absorption of antisera prepared against whole cells. The antigens were extracted both from isolated cilia and from whole cell bodies. Mild detergent extraction was found to be more efficient than mechanical disruption of the cells by freeze-thawing. The sedimentation behavior in sucrose density gradients of active H antigen was the same, whether freeze-thaw or detergent extracted; similarly, the sedimentation behavior of T was the same following the two extraction methods. Extraction with acetic acid, as reported by others, solubilized the same material as the detergent, but the acid denatured the antigen. An estimate of the molecular weight of the antigen of 29 000 for H and 23 000 for T was made.     

Light scattering by cellulose : IV. Fibers with helical morphology

Solid-state light scattering has been used to study the scattering by the helically wound microfibrils in wood fibers. Scattering envelopes have been recorded from a section of Eastern spruce wood as well as a single fiber of Black spruce. Theoretical expressions for the intensity of light scattered by a continuous helix have been derived and found to be in fair agreement with the experimental results. A method of estimating the “pitch” and “tilt” of the helical segments is outlined.     

Filamentous bacterial viruses : I. DNA synthesis during the early stages of infection with fd

During the first ten minutes after infection of bacteria with fd, the rate of DNA synthesis in an infected culture becomes several-fold larger than the rate in a parallel uninfected culture. This stimulation of rate is due to the synthesis of 100 to 200 double-stranded forms of viral DNA, superimposed on continuing bacterial DNA synthesis. At the end of the ten-minute period, the rate of viral plus bacterial DNA synthesis stops increasing, and remains constant for the next 50 minutes. The abrupt decrease in acceleration of net DNA synthesis corresponds in time to the onset of synthesis of single-stranded viral DNA.     

Solubilization of Trichoplusia ni granulosis virus proteinic crystal: I. Kinetics

Methods for the solubilization of an insect granulosis virus capsule from Trichoplusia ni were studied using turbidity measurements. The solubilization in the solvents employed was most strongly influenced by pH. Various alcohols and hydrogen bond cleaving agents also enhanced solubilization. The most effective solvent tested at pH′s close to neutrality was 60% n-propanol saturated with guanidine. HCl. The effectiveness of this solvent was minimal at pH 5.2. It was shown that the time courses of the solubilization were generally composed of three phases. A plot of the third phase levels versus pH indicated a normal distribution of those capsules or capsular fragments in resisting solubilization. Validity of the calculation of rate constants for the dissociation reaction in the second phase was discussed. Logarithm of the rate constant showed a linear relationship with the reciprocal of absolute temperature. The activation energy for the dissociation calculated from this relationship using the Arrhenius equation indicated that hydrophobic and hydrogen binding forces play the major roles for the stability of the crystalline structure of the capsular protein. Inic binding forces were estimated to be of minor importance.     

The oxidation of D-glucose and D-fructose with oxygen in aqueous,alkaline solutions : Part II. The overall kinetics

Based on a previously reported, integral reaction-scheme, a very simple, kinetic model for the homogeneous oxidation of D-glucose and D-fructose in aqueous, alkaline solutions has been developed. It involves the influence of the type and concentration of the hexose, the hydroxyl-ion concentration, the oxygen concentration in the liquid phase, and the temperature on the rate of formation of the acidic reaction products. No attention is paid to the product distribution.     

Analysis of 5-methylcytosine in DNA: II. Gas chromatography

A method for analyzing 5-methylcytosine in DNA by gas chromatography is described. The method is based on degradation of the DNA to its free bases by treatment with trifluoroacetic acid and gas chromatography of the trimethylsilyl derivatives of the free bases. Chromatography of microgram amounts of derivatized material is conducted at isothermal conditions using a 3% SE-30 or 2% OV-225 column. The peak areas corresponding to cytosine and 5-methylcytosine are used to calculate the 5-methylcytosine/cytosine molar ratio in DNA. The lower limit for detection of 5-methylcytosine in DNA by this method is a 5-methylcytosine/cytosine molar ratio of 0.001.