A method of calculation of accessibility to solvent of aromatic amino acid residues of proteins in water-organic mixtures]

Suggested method for calculation of solvent accessibility of tryptophan and tyrosine residues in water-organic mixtures is based on evaluation of second order derivatives of UV spectra. Second order derivative of the spectrum enable differentiation between direct effects of the organic solvent on spectral characteristics of exposed aromatic amino acid residues and the effect of the organic solvent on protein conformation. The method is suitable for calculation of exposition of tryptophan in water-organic mixtures if the content of tyrosine amino acid residues in protein does not exceed the content of tryptophan. Similar method of calculation of exposition of tyrosine residues can be used in proteins when the content of tyrosine is at least 5-fold higher than the content of tryptophan. For example, solvent accessibility of tryptophan residues of chymotrypsin is calculated in the presence of various organic solvents including ethanol, dioxane, and dimethyl formamide.     

Infectivity of the DNA of PM-2 phage

The infectivity of PM-2 phage free DNA was studied versus competent cells of marine bacteria Pseudomonas Bal-31 depending on the time of incubation with the bacterial cells, on the DNA and calcium concentration in the solution. Optimal conditions for the infection are the following: DNA concentration about 3 microgram/ml, CaCl2 concentration 0.1 M, incubation time 20 min.     

A note on "on the representation of language in the right hemisphere of right-handed people"

The effects of overstimulation of the thyroid gland induced by the feeding or rapeseed meal or thiouracil during the growing period persisted for as long as 75 weeks after withdrawal of the source of goitrogen from the diet. Thyroid weight, thyroid iodine content and radioiodine uptake were all increased in birds which had received goitrogen during the growing period. Follicle diameter was greater and the height of epithelial cells was lower than in control birds. The thyroid changes in these birds were deduced to be compensatory because production characteristics were normal and distribution of a dose of radioiodine into thyronines (T3 + T4) was similar in the birds which had received goitrogen during the growing period and in the control birds. Birds which were being fed rapeseed meal at the time the thyroid gland were examined showed effects which varied in magnitude according to the length of time over which rapeseed meal had been fed. Thyroid weight, follicle diameter, amount of epithelial tissue present and the total amount of iodine in the thyroid glands increased, whereas coupling efficiency (radioiodine-labelled T3 + T4)/(monoiodotyrosine/diiodotyrosine) declined with time.     

Change in lipid composition and lipid peroxidation rate in brain tissue under conditions of thymic hormone deficiency

Experiments on mature male rats have shown that 3 and 6 months after removal of the brain thymus, the level of total lipids in all cell centrifugate fractions (homogenate, supramitochondrial and mitochondrial fractions), which was followed by the higher rate of lipid peroxidation and the lower activity of cellular compartments, the spectrum imbalance of lipid fractions with predominant increases in the levels of phospholipids and free cholesterol. It is suggested that these changes make a contribution to the dysfunction of brain structures and participate in regulatory processes in thymectomy.     

Histamine levels in the blood of humans experimental animals under normal conditions and following vaccination]

The authors present the results of study of the blood histamine content in intact rabbits and in the animals to which commercial vaccines with a different degree of reactogenic property for man were administered. The blood histamine level was also studied in practically healthy individuals and in those vaccinated with inactivated tick-borne encephalitis vaccine. The blood histamine content varied in intact rabbits from 4 to 10 microgram/ml, averaging 6.4 +/- 0.09 microgram/ml. Animal immunization caused elevation of the blood histamine content correlating with the reactogenic properties of the preparations for man: vaccines with low reactogenic properties--inactivated encephalitis and live measles vaccine produced no significant changes in the index under study; as to the typhoid vaccine with sextatoxoid, and smallpox vaccine with marked reactogenic properties--they stimulated significant histaminemia in rabbits. Revaccination of man against tick-borne encephalitis with the inactivated cultural vaccine caused an increase in the blood histamine content.     

Faster synthesis and slower degradation of liver protein during developmental growth

A study is presented of the liver protein gain during the early stages of postnatal development. Fractional rates of protein synthesis and degradation were determined in vivo in livers of 4-day-old mice. At this age, liver protein accumulated at a rate of 18% per day. Synthesis was measured after the injection of massive amounts of radioactive leucine. Degradation was extimated as the balance between synthesis and accumulation of stable liver proteins, or from the disappearance of radioactivity from liver protein previously labelled by the administration of NaH14CO3. We found that the neonatal livers: (1) synthesize 139% as much protein per unit time and unit mass as adult tissue, which is accounted for by a higher ribosome concentration (synthesis per mg of RNA was the same); (2) retain 39% of the newly synthesized protein as stable liver components (compared with 48% in adult mice); (3) degrade protein at 56% of the rate in the adult liver. This lower rate of degradation is quantitatively the most significant difference between the growing and non-growing liver.     

Stepwise synthesis of oligonucleotides. XXII. The synthesis of Tpsi-loop fragments of yeast tRNAIVal and their analogs

The method of the combined use of nucleolytic enzymes was used for the synthesis of Tpsi-loop fragments of yeast valine tRNA and their analogs. Dinucleoside monophosphates, trinucleoside diphosphates and tetranucleoside triphosphates having the sequences of fragments 54-57 and 59-62 or their analogs were synthesized.     

The effect of NSAID on T-cell ratios in marginal periodontitis

The use of NSAID in the treatment of periodontal disease can augment the conventional periodontal therapy. NSAID can block prostaglandin synthesis which is responsible for the progression of periodontal disease. Inhibition of prostaglandin synthesis reduces the alveolar bone loss, loss of attachment, gingival inflammation and consequently pocket depth. Results of the present study show that the use of NSAID increases the T-cell ratios indicating an improvement of T-cell function which is represented clinically by the reduction in G.I scores.