Low Molecular Material Research Articles

Formula omitted][formula omitted] effect of d-lysergic acid diethylamide on immunoglobulin synthesis

Rabbit anti-fluorescyl antibody producing lymphoid cells incubated in vitro with LSD do not secrete the 7S form of immunoglobulin. The low molecular weight extracellular labeled material shows no measurable anti-fluorescyl antibody activity. Results indicate that during a short incubation period LSD interferes with tryptophan incorporation into antibody protein.

Kinetics of osmoregulation in the crab Carcinus maenas

When shore crabs Carcinus maenas are transferred from 11 to 38‰ S at 11°C, new constant levels of hemolymph freezing points and of concentrations of Na, K, Ca, and Mg in the hemolymph are accomplished within 24h. From a decrease in serum protein and in serum free amino acids and an increase in the relative amounts of individual essential free amino acids in the body fluids of whole crabs, a participation of proteolytic activities and a transport of amino acids from hemolymph to cell is deduced; the stationary concentration of total intracellular free amino acids increases up to a nearly two-fold value, compared with the concentration in crabs remaining in diluted sea water. Also, the low molecular neutral sugars increase in whole crabs after high salinity stress, reaching values of more than two-fold initial concentrations within a period of 10 days. This increase is fully accounted for by a 6.7-fold increase in trehalose levels. The processes of increasing the concentrations of low molecular organic material seem to be slower than those of establishing new osmotic pressures in the hemolymph. The oxygen consumption decreases by 30 to 45% to new constant values within 8 to 12 h after the salinity change from 11 to 38‰, reflecting similar kinetics as the establishment of new osmotic pressures in the hemolymph.

Antigen-free medium for cultivation of Haemophilus influenzae, AFH-medium.

An antigen‐free medium, AFH medium, for cultivation of H. influenzae is described. The medium is prepared from trypticase‐yeast autolysate, filtrated through a Sephadex G‐25 column. For the medium base only the fractions containing low molecular material were utilized. Addition of different amounts of salt and buffer was tested and the effect of the initial pH of the medium was studied. The amount of glucose consumed during growth was measured with a glucose oxidase test. The AFH medium provided luxuriant growth of all tested strains. The bacterial yield in the fluid medium was 1 times 1010‐1 times 1011 per ml and overnight cultures on the solid medium resulted in colonies 1–2 mm in diameter.

Experiments on the chemical transfer of memory from color-trained goldfish to untrained animals

36–48 h after the i.p. injection of a low molecular brain extract prepared from colour-trained goldfishes into naive goldfish, these recipients show positive reactions comparable to those shown by the donors. 12–24 h after the injection, the recipients showed an increased activity. No changes in behaviour have been noticed in the recipients of i.p. injections of low molecular brain material from untrained donor fish.

Light- and electronmicroscopical observations on the saccus vasculosus of the rainbow trout.

The saccus vasculosus of the rainbow trout, a sac-like outgrowing of the basis of the diencephalon consists of a strongly undulated epithelial wall, separating the cerebrospinal fluid from the endomeningeal matrix fluid. This epithelium is built up by highly specialized coronet cells, glial cells and peculiar so-called pseudo-coronet cells. The coronet cells extend from the ventricular- to the meningeal border. Morphological evidence is put forward indicating that transport of low molecular material might be the main function of these cells. Several cytochemical data support this hypothesis. A possible repulsion and renewal of globules of the coronet cells may represent steps in the functional cycle of these cells. Concerning the transport function, the observation of open connections between the lumina of the blood sinuses and the endomeningeal spaces might be important.

Evidence for a lipid activator of prophenolase in Tenebrio molitor

It has been shown that neither the soluble proteins nor the separated soluble low molecular material of Tenebrio tissue homogenates could activate samples of latent phenolase. Only the precipitate after centrifugation of a larval homogenate contained a thermostable factor able to convert the prophenolase into an active enzyme. This factor, the presence of which could be demonstrated in larval integuments, was a lipid. Further analysis showed that especially C-18 fatty acids exercise a high activating power on latent phenolase. As lipase activity was detected in the subcuticular fat and tracheal oenocytes, a hypothetical mechanism for the activation process was drawn up considering published data.

Chemical Structure and Properties of Heat Treated Coal in the Early State of Carbonization (XIV)

Nine vitrains (72. 7-90.7%C) were carbonized up to the temperatures between 320 and 600°C in a step of 20°C. The temperature was rised at the rate of 3°C/min. and the final temperature was kept for 10 minutes. The chars thus obtained were examined by X-band ESR spectrometer. ESR spectra were observed in vacuum (10-4-10-5 torr.), in air, in ethylene diamine after heating with it at 180°C and in air after washing with methanol and hydrochloric acid. Spin concentration (No.of spin/g of char) increased with rising temperature and it was noticed that the increase in spin concentration took place considerably even at temperatures as low as 320-380°C where no appreciable weight loss was observed by thermogravimetry. All of the chars, excepting these obtained at temperatures above 540°C, decreased their spin concentration when they were heated with ethylene diamine and the ΔHmsl observed in ethylene diamine kept constant value for each individual vitrains while the ΔHmsl observed in vacuum varied considerably. By washing the chars heated with ethylene diamine the spin concentration was recovered almost quantitatively for the chars obtained at temperature above 460°C, but not quantitatively for the other chars. It was observed that the recovery of spin concentration seemed difficult for some of chars which were obtained at temperatures between 400 and 440°C.It was assumed that the increase in spin concentration which was observed at low temperatures took place as a result of coming loose of the low molecular materials, on the analogy of the fact that chloroform-extract increases at the temperature. The spin centres which form and exist at temperatures below 500°C were considered to be similar to those exist in original coal in nature although as temperature gets near 500°C they vary gradually. It would be concluded that the spin centres of coal, especially of bituminos coal, are aliphatic or alicyclic in natue at temperatures below 500°C and above 500°C they become aromatic in nature.

Molecular weight distribution and environmental stress cracking of linear polyethylene

AbstractMolecular weight distributions of both Phillips and Zieglertype high density polyethylenes were determined following fractionation of the polymer samples using a column elution technique. The Wesslau log normal distribution function was used to describe the distributions of the resins investigated. Resistance to environmental stress rupture of speciments cut from compression molded plaques of these samples was measured by the constant tensile loading procedure. Data are presented showing annealed resins with “broad” molecular weight distributions, characterized particularly by a quantity of low molecular weigt material and a high molecular weight “tail,” to have poorer stress crack resistance than samples having a “narrow” molecular weight distribution. Stress crack resistance of specimens quenched from the melt, however, tends to improve for “broad” distribution resins, while decrasing for those polyethylenes having a “narrow” molecualar weigt distribution. Differences in crystal structure are used to explain the physical bassis for these effects.

Structural Changes Induced in Solid Dextran by Irradiation with Gamma Rays.

Dextran samples with various molecular properties were irradiated in air and in vacuum by gamma rays. Degradation occurs as ls evidenced from changes in molecular weight. The rate of degradation is faster in oxygen but less reproducible. The energy per broken bond is in vacuum the same for all samples (19 ev) and it does not change with lncreasing dosage up to 18 Mrad. Gel filtration experiments have shown that irradiation in oxygen gives a molecular weight distribution which contains a larger weight fraction of low molecular material. Electron spin resonance data show that very stable free radicals are formed. A hypothesis is put forward that primarily a radical ion is formed which then dissociates into a positive ion and an alkoxy radical. The change in branching during the degradation indicates that simultaneous bond scission and rearrangements of the molecules occur. An increase in branching is typical for molecules having an initially low degree of branching, while a high number of branches originally will lead to the formation of less branched molecules. This is explained as due to the spatial conditions along the chain. In all cases the polymolecularity of the samples increases during the degradation. (auth)