New Gene Crt(Curly Roots) Controlling Pea (Pisum sativum L.) Root Development

Using ethyl methane sulfonate (EMS) treatment of the seeds ofline SGE, a new mutant of pea (Pisum sativum L.) with alterationsin root development was obtained. The mutant phenotype dependson the density of the growth substrate: on sand (a high densitysubstrate) the mutant forms a small compact curly root systemwhereas on vermiculite (a low density substrate) differencesbetween the root systems of the mutant and wild type plantsare less pronounced. Genetic analysis revealed that the mutantcarries a mutation in a new pea gene designedcrt (curly roots).Gene crt has been localized in pea linkage group V. The mutantline named SGEcrt showed increased sensitivity to exogenousauxin and an increased concentration of endogenous indole-3-aceticacid (IAA) in comparison with the wild type line SGE. Copyright2000 Annals of Botany Company Pisum sativum L., root development, garden pea mutant, curly roots, auxin, environmental stimulus response     

Effect of precursors on biosynthesis of monensins A and B

Precursors of monensins (acetate, propionate, butyrate, isobutyrate) affect the total production and the relative proportion of monensins A and B. Addition of propionate into the fermentation medium causes a prevalence of monensin B whereas butyrate and isobutyrate stimulate the production of monensin A and suppress the production of monensin B.     

Role of adrenergic structures in regulating the release by the intestines of hemocoagulating compounds into the blood stream

Experiments on cats were made to study the capability of adrenaline, tropaphen and propranolol of influencing the intensity of the release of hemocoagulating compounds and anticoagulants from the intestinal vessels and tissues to the bloodstream (perfusate). Adrenaline was found to increase the coagulative activity of the perfusate, provoking an enhanced release into it of thromboplastin, an analogue of plasma factor V and antiheparin compounds and suppressing the release of antithromboplastins. The blockade of the alpha-adrenoreceptors was accompanied by a dramatic increase of antithromboplastins to the intestinal perfusate, whereas the depression of the activity of beta-adrenergic structures by reduction of the release of tissue thromboplastin inhibitors. It is concluded that regulation of the release of antithromboplastins in the intestine is mediated by the structures similar in their characteristics to alpha- and beta-adrenoreceptors.     

Analogs of oxytocin containing a modified peptide bond

Analogs of deamino-oxytocin and deamino-oxypressin containing a CH2-NH group instead of an amide bond between positions 8 and 9 were synthesized. All tested compounds exhibit significantly lowered biological activities.     

Tolerance induction by the peroral administration of protein antigens

The possibility of inducing systemic tolerance in animals by feeding them with ovalbumin and human serum was studied on mice, rats and rabbits. Antibodies to ovalbumin, human serum albumin and immunoglobulins (IgG, IgA, IgM) were determined by the passive hemagglutination test in the sera of the test and control animals after the second immunization made through a parenteral route. Tolerance to all the antigens under study was obtained in mice and rats, while in rabbits such feeding was found to produce the priming effect. The degree of tolerance was the greater, the more was the dose of the antigen and the longer was the period of feeding. Different proteins showed varying tolerogenic activity; the same degree of tolerance in mice was obtained by feeding them with IgG in a dose of 0.3-0.5 mg and with ovalbumin or human serum albumin in a dose of 6-12 mg (per gram of body weight). Tolerance was determined on day 3 after the course of feeding was over; in 3 weeks tolerance essentially decreased, and in 1.5-2 months it was replaced by normal reactiveness. Tolerance induced by the oral administration of antigens proved to be immunologically specific.     

A spectroscopic examination on intermolecular interaction of ergosterol with lecithin

The ergosterol and lecithin absorption IR-spectra were studied in a nonpolar anhydrous medium. The thermodynamical and spectral characteristics of dimeric associates and the enthalpy value for trimeric associates of this sterol are determined. Thermodynamical and spectral parameters of ergosterol intermolecular associates with lecithin in a nonpolar anhydrous medium are found. It is established that the intermolecular interaction of lecithin with ergosterol occurs according to the mechanism of hydrogen bond. A conclusion is drawn that the presence of binary bonds and methyl groups in the cyclic and aliphatic parts of the sterol molecule affects greatly the structure of the model membrane and its strength. It is shown that under conditions of the experiment the oxygen of the phosphate group contributes to formation of the molecular associates of lecithin with sterols and not that of the carbonyl group. The obtained experimental data may be at use when studying structural disturbances of native membranes in norm and with different pathologies.