[Secretion of Phenolic Compounds into Root Exudates of Pea Seedlings upon Inoculation with Rhizobium leguminosarum bv. viceae or Pseudomonas siringae pv. Pisi].

The content of apigenin, naringenin, pisatin, dibutyl-ortho-phthalate, and N-phenyl-2-naphthyl-amine were assayed in root exudates of pea (Pisum sativum L.) seedlings one day after their inoculation with Rhizobium leguminosarum, bv. viceae or Pseudomonas siringae pv. pisi, which represent, respectively, mutualistic and antagonistic strategies of interaction with a host plant. After inoculation with either bacteria, the concentrations of apigenin and pisatin in the root exudates were equal, whereas the concentrations of naringenin and N-phenyl-2-naphthylamine were different and those of dibutyl-o-phthalate were unchanged. A certain role is suggested for the phenolic compounds in an accomplishment of symbiotic relations of bacteria with a host plant.

[Effect of N-phenyl-2-naphthylamine on activity of adenylate cyclase signal system components and virulence of bacterial phytopathogens and mutualists].

The effect of N-phenyl-2-naphthylamine, negative allelochemical isolated from the exudates of roots of pea (Pisum sativum L.), on the growth and activity of the adenylate cyclase signal system and virulence factors of the bacteria Rhizobium leguminosarum bv. viciae and Pseudomonas siringae pv. pisi was studied. It was demonstrated that N-phenyl-2-naphthylamine at a physiological concentration nonspecifically inhibited the growth of these bacteria in both planktonic cultures and biofilms. One of the reasons for this phenomenon is the reduction of intra- and extracellular concentrations of cAMP due to greater activation of phosphodiesterase, which disrupts cAMP, in comparison to soluble adenylyl cyclase, which synthesizes it. At the same time, N-phenyl-2-naphthylamine did not affect activity of either membrane-bound adenylyl cyclase or bacterial virulence factors.

[Role of allelopathic compositions in the regulation and development of legume-rhizobial symbiosis].

It was discovered that aromatic compounds isolated from root exudates of three legume species (Pisum sativum L., Vicia faba L. var. major Hartz, and Glycine max L. MERR) and identified as N-phenyl-2-naphthyl amine, dibutyl, and dioctyl esters of orthophthalic acid, which are known to work as negative allelopathic substances, are involved in the regulation of legume-rhizobial symbiosis formation after the inoculation of roots with rhizobia under unfavorable conditions for symbiosis.

[Oxidation processes at initial stages of interaction of root nodule bacteria (Rhizobium leguminosarum) and pea (Pisum sativum L.): a review].

A possible physiological mechanism of legume-Rhizobium symbiosis, consisting in regulation of the intensity of oxidation processes by the microsymbiont in response to infection with Rhizobium, was analyzed using our own and published data. The results used in the analysis included data on the content of reactive oxygen species (O2*-, and H2O2), activity of antioxidant enzymes (superoxide dismutase, catalase, and peroxidase), and intensity of lipid peroxidation proceeding with the involvement of lipophilic phenolic compounds of the microsymbiont.

[The effect of the phenolic compounds exuded by pea roots in darkness on the reproduction of Rhizobium].

The exudation, composition, and biological activity of the phenolic compounds (PC) of pea (Pisum sativum L.) roots in the light and darkness were studied. The roots of leguminous plants grown for 5 days in darkness exuded a smaller amount of PC that displayed a weaker stimulation of Rhizobium reproduction. Moreover, the root exudates contained antimicrobial compounds, stilbenes. It is assumed that a lower PC exudation by roots and the specific features of PC composition influencing the biological activity are among the reasons causing a delayed nodulation of legumes grown in darkness.

[The defense and regulatory mechanisms during development of legume-Rhizobium symbiosis].

The roles of indolylacetic acid, the peroxidase system, catalase, active oxygen species, and phenolic compounds in the physiological and biochemical mechanisms involved in the autoregulation of nodulation in the developing legume-Rhizobium symbiosis were studied. It was inferred that the concentration of indolylacetic acid in the roots of inoculated plants, controlled by the enzymes of the peroxidase complex, is the signal permitting or limiting nodulation at the initial stages of symbiotic interaction. Presumably, the change in the level of active oxygen species is determined by an antioxidant activity of phenolic compounds. During the development of symbiosis, phytohormones, antioxidant enzymes, and active oxygen species may be involved in the regulation of infection via both a direct antibacterial action and regulation of functional activity of the host plant defense systems.

[Possible involvement of hydrogen peroxide and salicylic acid in the legume-rhizobium symbiosis].

H2O2 content was studied in the roots and epicotyls of pea (Pisum sativum L.) with normal (cultivar Marat) and disturbed (non-nodulating mutant K14 and hypernodulating mutant Nod3) regulation of root nodulation after inoculation with active industrial strain of Rhizobium leguminosarum by. viceae 250a/CIAM 1026. Pea biotypes differed by H2O2 content in the roots and epicotyls. Exogenous salicylic acid (SA) (0.2 mM) affected H2O2 and SA contents in the roots in an inoculation-dependent manner. The involvement of hydrogen peroxide and SA as signaling molecules as well as of antibacterial agents in the pea-rhizobium interaction at the initial stages of symbiosis is proposed.

[Temperature impact on localization of "free" phenolic compounds in the root tissues and deformation of root hairs in pea seedlings inoculated by Rhizobium].

The study was focused on localization of "free" phenolic compounds in pea Pisum sativum L. seedling roots grown at 22 and 8 degrees C 24 h after their inoculation with Rhizobium leguminosarum bv. viceae bacteria. A comparison of phenolic compound distribution along the root in root tissues, and results of observation of root hair development on the root surface, response of root hairs to inoculation, manifesting itself in various deformation degree (bends, twists, ect.) enabled us to reveal differences between roots grown at different temperatures. These differences are basically referred to a sector localized 0-5 mm away from the root tip containing meristematic and extending cells. A distribution of phenolic compounds in sectors with root hairs responding to inoculation by various degrees of contortion practically did not depend on the temperature of plant growth. The evidence provided in the course of this work enabled us to suggest that inhibition of pea root infection at low temperature is caused by decelerated growth processes characteristic of both the root itself and root hairs, as well by a slow increase in the root hair zone.

[The early detection of allergic dermatoses and mycoses of the feet in workers in contact with phenol-formaldehyde resins]. / Rannee vyiavlenie allergicheskikh dermatozov i mikozov stop u rabochikh, kontaktiruiushchikh s fenolformal'degidnymi smolami.

Hypersensitivity to phenolformaldehyde resins was detected in 16.2% of workers exposed to them, allergic dermatitis and eczemas in 21.5%, mycoses of the soles in 13.5%, premorbid shifts in half of the examinees. Mycoses of the soles prevailed in subjects with a history of dermatitis and in patients suffering from allergic dermatoses.

[Dopamine receptors of the smooth muscles]. / O dofaminovykh retseptorakh gladkikh myshts

It is shown that the interuption of sympathetic nerves in the smooth muscles of the deferent duct or ejejunum of rats achieved by a 4-day keeping of the duct in cold or by the reserpine treatment of the animals does not produce any essential effect on the dopamine action. The contraction of smooth muscles in the isolated deferent duct, mesenteric and renal vessels of rats is effectively eliminated by alpha-andrenolytics (dihydroergotoxin, phentolamine), while the inhibitory effects of dopamine (lowering of vasotonicity of the rats' jejunum tone) are suppressed with propranolol. Galoperidol and methylergometrin display in experiments with smooth muscle organs but a low degree of antagonism to dopamine. The activity of phentolamine as an antagonist of norepinephrine and dopamine in the deferent duct is identical.